[PATCH] arm64: dts: aspeed: Enlarge AST2700 EVB kernel partition to 12 MiB

[Andrew Jeffery]

Hi Cooper,

On Thu, 2026-10-29 at 15:25 +0800, Cooper Huang wrote:
> From: Chin-Ting Kuo <chin-ting_kuo at aspeedtech.com>
> 
> The 128 MiB flash layout of the AST2700 EVB reserves 9 MiB for the
> kernel FIT image. A FIT image containing an LZMA-compressed kernel,
> the DTB and an initramfs is already close to that size, leaving little
> room for the kernel to grow.
> 
> Grow the kernel partition to 12 MiB and take the 3 MiB from rofs,

Why 12MiB? Why only take 3MiB?

> which now starts at 0x1020000 and shrinks from 82.875 MiB to
> 79.875 MiB. rofs still ends at 0x6000000, so the u-boot, u-boot-env
> and rwfs partitions are unchanged.
> 
> This is the same layout used by the OpenBMC images ASPEED provides
> for the EVB [1],
> 

Why was what was sent upstream different to what you were doing
elsewhere in the software stack? It seems oddly incoherent. 

>  so the rofs partition described by the device tree
> also matches where those images place the filesystem.
> 
> Link: https://github.com/AspeedTech-BMC/openbmc/blob/438e761ed38644b77ba704c984cb607649bf2724/meta-aspeed-sdk/meta-ast2700-sdk/conf/machine/ast2700-default.conf [1]
> Signed-off-by: Chin-Ting Kuo <chin-ting_kuo at aspeedtech.com>
> Signed-off-by: Cooper Huang <cooper_huang at aspeedtech.com>
> ---
> Notes:
> - "Already close to that size": with mainline at c339f4010dea
>   (v7.3-17997), ASPEED's aspeed_g7_defconfig [2] and GCC 13.2, a FIT

A bit of a tangent, but GCC 13.2 is over 3 years old at this point.
Debian stable ships 14.2. Why such an old compiler?

>   image with the LZMA-compressed kernel, ast2700-evb.dtb and the
>   OpenBMC phosphor initramfs is about 8.99 MiB, less than 20 KiB

What are your measured sizes for the kernel vs the initramfs?

Is the initramfs content reasonable?

Andrew

>   below 9 MiB (the exact size varies by a few KiB between builds).
> - Upstream OpenBMC's AST2700 machines use the static-norootfs layout
>   (no rofs) and are unaffected; the rwfs offset does not change.
> 
> [2] https://github.com/AspeedTech-BMC/linux/blob/76457d3afe2bd4022ca82dd9eb8fc48b84f0e9ab/arch/arm64/configs/aspeed_g7_defconfig
> ---
>  arch/arm64/boot/dts/aspeed/aspeed-evb-flash-layout-128.dtsi | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/boot/dts/aspeed/aspeed-evb-flash-layout-128.dtsi b/arch/arm64/boot/dts/aspeed/aspeed-evb-flash-layout-128.dtsi
> index b54915f06efd..f54d53077538 100644
> --- a/arch/arm64/boot/dts/aspeed/aspeed-evb-flash-layout-128.dtsi
> +++ b/arch/arm64/boot/dts/aspeed/aspeed-evb-flash-layout-128.dtsi
> @@ -16,12 +16,12 @@ u-boot-env at 400000 {
>  	};
>  
>  	kernel at 420000 {
> -		reg = <0x420000 0x900000>; // 9MB
> +		reg = <0x420000 0xc00000>; // 12MB
>  		label = "kernel";
>  	};
>  
> -	rofs at d20000 {
> -		reg = <0xd20000 0x52E0000>; // 82.875MB
> +	rofs at 1020000 {
> +		reg = <0x1020000 0x4fe0000>; // 79.875MB
>  		label = "rofs";
>  	};
>  
> 
> ---
> base-commit: cee9395acd8043be0644b25c34bfa86623f2b935
> change-id: 20261029-ast2700-evb-kernel-part-63b3c998ea6e
> 
> Best regards,