Re: [PATCH v5 4/6] arm64: dts: imx8mm: imx8mp: Add CM DTOs for Data Modul i.MX8M Mini and Plus eDM SBC

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The CM4 devicetree overlay for the i.MX8MM board hardcodes reserved memory regions at physical addresses that lie outside the RAM boundaries of the 1 GiB variant of the board.
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--- Patch [4]: [PATCH v5 4/6] arm64: dts: imx8mm: imx8mp: Add CM DTOs for Data Modul i.MX8M Mini and Plus eDM SBC ---
commit 570590d387e46a557b9ab429099f8826e9336ea2
Author: Marek Vasut <marex@nabladev.com>

arm64: dts: imx8mm: imx8mp: Add CM DTOs for Data Modul i.MX8M Mini and Plus eDM SBC

This commit adds device tree overlays which provide CM4/CM7 extras for
the Data Modul i.MX8M Mini and Plus eDM SBCs. It allows CM4/CM7 firmware
to be used with remoteproc and rpmsg without imposing overhead on all users.

[ ... ]
> diff --git a/arch/arm64/boot/dts/freescale/imx8mm-data-modul-edm-sbc-overlay-cm4.dtso b/arch/arm64/boot/dts/freescale/imx8mm-data-modul-edm-sbc-overlay-cm4.dtso
> new file mode 100644
> index 0000000000000..0bd770af2a68c
> --- /dev/null
> +++ b/arch/arm64/boot/dts/freescale/imx8mm-data-modul-edm-sbc-overlay-cm4.dtso
[ ... ]
> +	reserved-memory {	/* CM4 reserved memory */
> +		#address-cells = <2>;
> +		#size-cells = <2>;
> +		ranges;
> +
> +		m_core_reserved: m_core@b7000000 {
> +			reg = <0 0xb7000000 0 0x1000000>;
> +			no-map;
> +		};
> +
> +		vdev0vring0: vdev0vring0@b8000000 {
> +			reg = <0 0xb8000000 0 0x8000>;
> +			no-map;
> +		};

[Severity: High]
Will applying this overlay on the 1 GiB variant of the board cause a crash?

The base board imx8mm-data-modul-edm-sbc.dts supports 1, 2, or 4 GiB variants 
with physical memory starting at 0x40000000. On a 1 GiB variant, physical 
memory ends at 0x7FFFFFFF.

Since these memory regions are hardcoded at physical addresses starting at
0xb7000000 and 0xb8000000, they fall outside the available DRAM for 1 GiB
boards. 

When the remoteproc driver probes and attempts to map and initialize these 
reserved memory regions, will it access unbacked physical memory and trigger 
a synchronous external abort?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260716055751.279033-1-marex@nabladev.com?part=4