Re: [PATCH v4 08/10] rockchip: binman: Use the skip-at-start prop in simple-bin image

[Quentin Schulz <quentin.schulz@cherry.de>]

Hi Jonas, Simon,

On 3/29/25 4:06 PM, Jonas Karlman wrote:
> From: Simon Glass <sjg@chromium.org>
> 
> The simple-bin image is normally written to MMC media at block 64, which
> is a 32K offset from start of storage media.
> 
> Set the skip-at-start property to 0x8000 (32 KiB) so that fdtmap and
> other embedded binman symbols in the output binary is referencing image
> offsets correctly.
> 

Shouldn't we have this commit BEFORE we add the `fdtmap` node since we 
know it's wrong before this commit?

> Signed-off-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
> ---
> Changes in v4:
> - Drop defconfig changes
> - Split from "VBE serial part H: Implement VBE on Rockchip RK3399"
> 
> Changes in v2:
> - Move this patch to the end of the series
> - Drop 0x8000 offset for SPI
> ---
>   arch/arm/dts/rockchip-u-boot.dtsi | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/dts/rockchip-u-boot.dtsi b/arch/arm/dts/rockchip-u-boot.dtsi
> index fb38b7b80c43..65b81bf58626 100644
> --- a/arch/arm/dts/rockchip-u-boot.dtsi
> +++ b/arch/arm/dts/rockchip-u-boot.dtsi
> @@ -154,6 +154,7 @@
>   	simple-bin {
>   		filename = "u-boot-rockchip.bin";
>   		pad-byte = <0xff>;
> +		skip-at-start = <0x8000>;
>   
>   		mkimage {
>   			filename = "idbloader.img";
> @@ -178,7 +179,7 @@
>   #else
>   		u-boot-img {
>   #endif
> -			offset = <CONFIG_SPL_PAD_TO>;
> +			offset = <(CONFIG_SPL_PAD_TO + 0x8000)>;

This is confusing. The documentation states:

"""
offset:
     This sets the offset of an entry within the image or section containing
     it.
"""

My understanding is that it should be relative to the beginning of the 
image but this now needs the knowledge of where it will be stored on the 
MMC device (via the value in skip-at-start).

Why is skip-at-start automatically deducted from offset?

Cheers,
Quentin