linux-kernel - Re: [PATCH v7 06/11] arm64: dts: ti: k3-am62a7-sk: Enable IPC with remote processors

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Message-ID: <20250419150451.v3jgtgp4yisou65u@bryanbrattlof.com>
Date: Sat, 19 Apr 2025 10:04:51 -0500
From: Bryan Brattlof <bb@...com>
To: Judith Mendez <jm@...com>
CC: Nishanth Menon <nm@...com>, Vignesh Raghavendra <vigneshr@...com>,
        Tero
 Kristo <kristo@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof
 Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, Hari Nagalla <hnagalla@...com>,
        Beleswar
 Prasad <b-padhi@...com>, Andrew Davis <afd@...com>,
        Markus Schneider-Pargmann
	<msp@...libre.com>,
        Devarsh Thakkar <devarsht@...v0571a.ent.ti.com>
Subject: Re: [PATCH v7 06/11] arm64: dts: ti: k3-am62a7-sk: Enable IPC with
 remote processors

On April 15, 2025 thus sayeth Judith Mendez:
> From: Devarsh Thakkar <devarsht@...com>
> 
> For each remote proc, reserve memory for IPC and bind the mailbox
> assignments. Two memory regions are reserved for each remote processor.
> The first region of 1MB of memory is used for Vring shared buffers
> and the second region is used as external memory to the remote processor
> for the resource table and for tracebuffer allocations.
> 
> Signed-off-by: Devarsh Thakkar <devarsht@...com>
> Signed-off-by: Hari Nagalla <hnagalla@...com>
> Signed-off-by: Judith Mendez <jm@...com>
> Acked-by: Andrew Davis <afd@...com>
> Reviewed-by: Beleswar Padhi <b-padhi@...com>
> Reviewed-by: Jai Luthra <jai.luthra@...asonboard.com>
> ---
>  arch/arm64/boot/dts/ti/k3-am62a7-sk.dts | 96 +++++++++++++++++++++++--
>  1 file changed, 90 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts b/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
> index 1c9d95696c839..7d817b447c1d0 100644
> --- a/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
> +++ b/arch/arm64/boot/dts/ti/k3-am62a7-sk.dts
> @@ -52,6 +52,42 @@ linux,cma {
>  			linux,cma-default;
>  		};
>  
> +		c7x_0_dma_memory_region: c7x-dma-memory@...00000 {
> +			compatible = "shared-dma-pool";
> +			reg = <0x00 0x99800000 0x00 0x100000>;
> +			no-map;
> +		};
> +
> +		c7x_0_memory_region: c7x-memory@...00000 {
> +			compatible = "shared-dma-pool";
> +			reg = <0x00 0x99900000 0x00 0xf00000>;
> +			no-map;
> +		};
> +

I know this has been a push for our IPC and MCU+ teams for a couple 
windows now, though I do want to point out that some AM62A devices 
(AM62A12AQMSIAMBRQ1) will not even have a C7x. 

It's relatively easy to cut nodes out that describe the hardware in the 
bootloaders, but once we start configuring them to demo something it 
becomes impossible to unwind that during boot.

We can clam we only support the superset devices but I just wanted to 
make this email so I could point people to it when they inevitably ask 
why their parts do not work out of the box with Linux.

Naked-by: Bryan Brattlof <bb@...com>

~Bryan

> +		mcu_r5fss0_core0_dma_memory_region: r5f-dma-memory@...00000 {
> +			compatible = "shared-dma-pool";
> +			reg = <0x00 0x9b800000 0x00 0x100000>;
> +			no-map;
> +		};
> +
> +		mcu_r5fss0_core0_memory_region: r5f-dma-memory@...00000 {
> +			compatible = "shared-dma-pool";
> +			reg = <0x00 0x9b900000 0x00 0xf00000>;
> +			no-map;
> +		};
> +
> +		wkup_r5fss0_core0_dma_memory_region: r5f-dma-memory@...00000 {
> +			compatible = "shared-dma-pool";
> +			reg = <0x00 0x9c800000 0x00 0x100000>;
> +			no-map;
> +		};
> +
> +		wkup_r5fss0_core0_memory_region: r5f-dma-memory@...00000 {
> +			compatible = "shared-dma-pool";
> +			reg = <0x00 0x9c900000 0x00 0xf00000>;
> +			no-map;
> +		};
> +
>  		secure_tfa_ddr: tfa@...80000 {
>  			reg = <0x00 0x9e780000 0x00 0x80000>;
>  			alignment = <0x1000>;
> @@ -63,12 +99,6 @@ secure_ddr: optee@...00000 {
>  			alignment = <0x1000>;
>  			no-map;
>  		};
> -
> -		wkup_r5fss0_core0_memory_region: r5f-dma-memory@...00000 {
> -			compatible = "shared-dma-pool";
> -			reg = <0x00 0x9c900000 0x00 0x01e00000>;
> -			no-map;
> -		};
>  	};
>  
>  	opp-table {
> @@ -741,3 +771,57 @@ dpi1_out: endpoint {
>  		};
>  	};
>  };
> +
> +&mailbox0_cluster0 {
> +	status = "okay";
> +
> +	mbox_r5_0: mbox-r5-0 {
> +		ti,mbox-rx = <0 0 0>;
> +		ti,mbox-tx = <1 0 0>;
> +	};
> +};
> +
> +&mailbox0_cluster1 {
> +	status = "okay";
> +
> +	mbox_c7x_0: mbox-c7x-0 {
> +		ti,mbox-rx = <0 0 0>;
> +		ti,mbox-tx = <1 0 0>;
> +	};
> +};
> +
> +&mailbox0_cluster2 {
> +	status = "okay";
> +
> +	mbox_mcu_r5_0: mbox-mcu-r5-0 {
> +		ti,mbox-rx = <0 0 0>;
> +		ti,mbox-tx = <1 0 0>;
> +	};
> +};
> +
> +&wkup_r5fss0 {
> +	status = "okay";
> +};
> +
> +&wkup_r5fss0_core0 {
> +	mboxes = <&mailbox0_cluster0>, <&mbox_r5_0>;
> +	memory-region = <&wkup_r5fss0_core0_dma_memory_region>,
> +			<&wkup_r5fss0_core0_memory_region>;
> +};
> +
> +&mcu_r5fss0 {
> +	status = "okay";
> +};
> +
> +&mcu_r5fss0_core0 {
> +	mboxes = <&mailbox0_cluster2>, <&mbox_mcu_r5_0>;
> +	memory-region = <&mcu_r5fss0_core0_dma_memory_region>,
> +			<&mcu_r5fss0_core0_memory_region>;
> +};
> +
> +&c7x_0 {
> +	mboxes = <&mailbox0_cluster1>, <&mbox_c7x_0>;
> +	memory-region = <&c7x_0_dma_memory_region>,
> +			<&c7x_0_memory_region>;
> +	status = "okay";
> +};
> -- 
> 2.49.0
>