linux-kernel - Re: [PATCH v4 6/9] arm64: dts: ti: k3-am62p5-sk: Enable IPC with remote processors

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Message-ID: <32358aa1-0c02-4f4d-9782-2d8376c0d9fc@ti.com>
Date: Fri, 7 Feb 2025 10:58:40 -0600
From: Andrew Davis <afd@...com>
To: Judith Mendez <jm@...com>, Nishanth Menon <nm@...com>,
        Vignesh Raghavendra
	<vigneshr@...com>
CC: 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>
Subject: Re: [PATCH v4 6/9] arm64: dts: ti: k3-am62p5-sk: Enable IPC with
 remote processors

On 2/6/25 5:51 PM, Judith Mendez wrote:
> 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>
> ---
> Changes since v3:
> - Add SRAM child node for am62p MCU R5 core 0
> ---
>   .../dts/ti/k3-am62p-j722s-common-mcu.dtsi     | 13 +++++
>   arch/arm64/boot/dts/ti/k3-am62p5-sk.dts       | 50 ++++++++++++++++---
>   2 files changed, 57 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-mcu.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-mcu.dtsi
> index b33aff0d65c9d..0be3463bc21c5 100644
> --- a/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-mcu.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-am62p-j722s-common-mcu.dtsi
> @@ -6,6 +6,18 @@
>    */
>   
>   &cbass_mcu {
> +	mcu_ram: sram@...00000 {
> +		compatible = "mmio-sram";
> +		reg = <0x00 0x79100000 0x00 0x80000>;
> +		ranges = <0x00 0x00 0x79100000 0x80000>;
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +
> +		mcu_sram1@0 {

What does this node do for us? Seems you reserve the whole SRAM
area from the start, but shouldn't the phandle in mcu_r5fss0_core0
point to this node? Or better it would use the normal SRAM API
to request an allocation from this region.

Since this is still not resolved, and you don't mention it in
the commit message, might be good to drop this SRAM part of this
patch and deal with this in a later series.

Andrew

> +			reg = <0x0 0x80000>;
> +		};
> +	};
> +
>   	mcu_pmx0: pinctrl@...4000 {
>   		compatible = "pinctrl-single";
>   		reg = <0x00 0x04084000 0x00 0x88>;
> @@ -213,6 +225,7 @@ mcu_r5fss0_core0: r5f@...00000 {
>   			ti,atcm-enable = <0>;
>   			ti,btcm-enable = <1>;
>   			ti,loczrama = <0>;
> +			sram = <&mcu_ram>;
>   		};
>   	};
>   };
> diff --git a/arch/arm64/boot/dts/ti/k3-am62p5-sk.dts b/arch/arm64/boot/dts/ti/k3-am62p5-sk.dts
> index ad71d2f27f538..9609727d042d3 100644
> --- a/arch/arm64/boot/dts/ti/k3-am62p5-sk.dts
> +++ b/arch/arm64/boot/dts/ti/k3-am62p5-sk.dts
> @@ -48,6 +48,30 @@ reserved-memory {
>   		#size-cells = <2>;
>   		ranges;
>   
> +		mcu_r5fss0_core0_dma_memory_region: mcu-r5fss-dma-memory-region@...00000 {
> +			compatible = "shared-dma-pool";
> +			reg = <0x00 0x9b800000 0x00 0x100000>;
> +			no-map;
> +		};
> +
> +		mcu_r5fss0_core0_memory_region: mcu-r5fss-memory-region@...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-memory@...00000 {
> +			compatible = "shared-dma-pool";
> +			reg = <0x00 0x9c900000 0x00 0x1e00000>;
> +			no-map;
> +		};
> +
>   		secure_tfa_ddr: tfa@...80000 {
>   			reg = <0x00 0x9e780000 0x00 0x80000>;
>   			no-map;
> @@ -57,12 +81,6 @@ secure_ddr: optee@...00000 {
>   			reg = <0x00 0x9e800000 0x00 0x01800000>; /* for OP-TEE */
>   			no-map;
>   		};
> -
> -		wkup_r5fss0_core0_memory_region: r5f-dma-memory@...00000 {
> -			compatible = "shared-dma-pool";
> -			reg = <0x00 0x9c900000 0x00 0x01e00000>;
> -			no-map;
> -		};
>   	};
>   
>   	vmain_pd: regulator-0 {
> @@ -638,6 +656,26 @@ mbox_mcu_r5_0: mbox-mcu-r5-0 {
>   	};
>   };
>   
> +&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_cluster1 &mbox_mcu_r5_0>;
> +	memory-region = <&mcu_r5fss0_core0_dma_memory_region>,
> +			<&mcu_r5fss0_core0_memory_region>;
> +};
> +
>   &main_uart0 {
>   	pinctrl-names = "default";
>   	pinctrl-0 = <&main_uart0_pins_default>;