Subject: Re: [PATCH v2 1/1] arm64: dts: ti: k3-j7: Reserve memory for LPM meta data

From: Nishanth Menon <[email-masked]>
Date: Tue, 5 May 2026 07:59:45 -0500

On 18:03-20260427, Richard Genoud (TI) wrote:
> From: Prasanth Babu Mantena <[email-masked]>
> 
> For TI SOCs J7200, J784S4, J722S, J721s2 which support low power modes,
> a chunk of memory is reserved for LPM meta data, which is needed for
> saving ATF context and the certificate information of ATF and OPTEE and
> DM image. This LPM metadata area is firewalled to be accessed only by
> TIFS.
> 
> U-Boot/TIFS will use this area to save and restore:
> - ATF context
> - ATF certificate information
> - OPTEE certificate information
> - DM image

DM image is loaded from storage, correct?
> 
> https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/pm/lpm.html#lpm-msg-lpm-save-addr
> 
> U-Boot has to parse and retrieve this area from the device tree, thus
> @lpm-memory node are used instead of the generic @memory.
> 
> Signed-off-by: Prasanth Babu Mantena <[email-masked]>
> Signed-off-by: Richard Genoud (TI) <[email-masked]>
> ---
>  arch/arm64/boot/dts/ti/k3-j7200-som-p0.dtsi  | 6 ++++++
>  arch/arm64/boot/dts/ti/k3-j721s2-som-p0.dtsi | 6 ++++++
>  arch/arm64/boot/dts/ti/k3-j722s-evm.dts      | 6 ++++++
>  arch/arm64/boot/dts/ti/k3-j742s2-evm.dts     | 9 +++++++++
>  arch/arm64/boot/dts/ti/k3-j784s4-evm.dts     | 9 ++++++---

Split this up into platform wise. I dont understand why you'd not modify
the ipc-firmware.dtsi and use the phandle similar to https://lore.kernel.org/all/[email-masked]/

Split the patches per ipc-firmware.dtsi as required.

>  5 files changed, 33 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/ti/k3-j7200-som-p0.dtsi b/arch/arm64/boot/dts/ti/k3-j7200-som-p0.dtsi
> index 5a8c2e707fde..756928a2d411 100644
> --- a/arch/arm64/boot/dts/ti/k3-j7200-som-p0.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-j7200-som-p0.dtsi
> @@ -40,6 +40,12 @@ mcu_r5fss0_core0_memory_region: memory@a0100000 {
>  			reg = <0x00 0xa0100000 0x00 0xf00000>;
>  			no-map;
>  		};
> +
> +		lpm_memory_region: lpm-memory@a4800000 {

vignesh already flagged this in previous revision - just use phandle
reference in u-boot and make this memory@

> +			reg = <0x00 0xa4800000 0x00 0x00300000>;
> +			no-map;
> +			bootph-all;
> +		};
>  	};
>  
>  	mux0: mux-controller-0 {
> diff --git a/arch/arm64/boot/dts/ti/k3-j721s2-som-p0.dtsi b/arch/arm64/boot/dts/ti/k3-j721s2-som-p0.dtsi
> index 12a38dd1514b..ceab8f057640 100644
> --- a/arch/arm64/boot/dts/ti/k3-j721s2-som-p0.dtsi
> +++ b/arch/arm64/boot/dts/ti/k3-j721s2-som-p0.dtsi
> @@ -42,6 +42,12 @@ mcu_r5fss0_core0_memory_region: memory@a0100000 {
>  			reg = <0x00 0xa0100000 0x00 0xf00000>;
>  			no-map;
>  		};
> +
> +		lpm_memory_region: lpm-memory@a9c00000 {
> +			reg = <0x00 0xa9c00000 0x00 0x00300000>;
> +			no-map;
> +			bootph-all;
> +		};
>  	};
>  
>  	mux0: mux-controller-0 {
> diff --git a/arch/arm64/boot/dts/ti/k3-j722s-evm.dts b/arch/arm64/boot/dts/ti/k3-j722s-evm.dts
> index e66330c71593..eebc5cc7d4cd 100644
> --- a/arch/arm64/boot/dts/ti/k3-j722s-evm.dts
> +++ b/arch/arm64/boot/dts/ti/k3-j722s-evm.dts
> @@ -63,6 +63,12 @@ wkup_r5fss0_core0_memory_region: memory@a0100000 {
>  			reg = <0x00 0xa0100000 0x00 0xf00000>;
>  			no-map;
>  		};
> +
> +		lpm_memory_region: lpm-memory@a6c00000 {
> +			reg = <0x00 0xa6c00000 0x00 0x00300000>;
> +			no-map;
> +			bootph-all;
> +		};
>  	};
>  
>  	vmain_pd: regulator-0 {
> diff --git a/arch/arm64/boot/dts/ti/k3-j742s2-evm.dts b/arch/arm64/boot/dts/ti/k3-j742s2-evm.dts
> index fcb7f05d7faf..d0752c8a6b37 100644
> --- a/arch/arm64/boot/dts/ti/k3-j742s2-evm.dts
> +++ b/arch/arm64/boot/dts/ti/k3-j742s2-evm.dts
> @@ -23,4 +23,13 @@ memory@80000000 {
>  		device_type = "memory";
>  		bootph-all;
>  	};
> +
> +};
> +
> +&reserved_memory {
> +	lpm_memory_region: lpm-memory@ab000000 {
> +		reg = <0x00 0xab000000 0x00 0x00300000>;
> +		no-map;
> +		bootph-all;
> +	};
>  };
> diff --git a/arch/arm64/boot/dts/ti/k3-j784s4-evm.dts b/arch/arm64/boot/dts/ti/k3-j784s4-evm.dts
> index 6c7458c76f53..114594f37f0b 100644
> --- a/arch/arm64/boot/dts/ti/k3-j784s4-evm.dts
> +++ b/arch/arm64/boot/dts/ti/k3-j784s4-evm.dts
> @@ -23,10 +23,13 @@ memory@80000000 {
>  		device_type = "memory";
>  		bootph-all;
>  	};
> +};
>  
> -	reserved_memory: reserved-memory {
> -		#address-cells = <2>;
> -		#size-cells = <2>;
> +&reserved_memory {
> +	lpm_memory_region: lpm-memory@ac000000 {
> +		reg = <0x00 0xac000000 0x00 0x00300000>;
> +		no-map;
> +		bootph-all;
>  	};
>  };
>  

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D
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