[PATCH] doc: rockchip: Clarify the rkspi image format further

[Quentin Schulz]

Hi all,

On 2/10/24 19:18, Dragan Simic wrote:
> [You don't often get email from dsimic at manjaro.org. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> 
> As discussed on the U-Boot mailing list, [1][2] only some Rockchip SoCs
> suffer from a bug in their BROMs that requires a specific format for their
> SPI images, which was the reason for the rkspi format to be introduced.
> 
> Improve the description of the rkspi format a bit to mention this, for
> future reference and to make understanding it easier.
> 
> [1] https://lore.kernel.org/u-boot/c32129ba-db25-4b9d-9a4a-032d88dfb9cd@kwiboo.se/
> [2] https://lore.kernel.org/u-boot/CACdvmAjfCWicRd=LKKyob7fZo79AFkUQKy0e1HBb0zyJuoO70g@mail.gmail.com/
> 
> Signed-off-by: Dragan Simic <dsimic at manjaro.org>
> ---
>   doc/README.rockchip | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/doc/README.rockchip b/doc/README.rockchip
> index 84caff8a24d3..e0c5c395ec6a 100644
> --- a/doc/README.rockchip
> +++ b/doc/README.rockchip
> @@ -649,7 +649,12 @@ sector is used. The header is the same as with rksd and the maximum size is
>   also 32KB (before spreading). The image should be written to the start of
>   SPI flash.
> 
> -See above for instructions on how to write a SPI image.
> +Only the BROMs of some Rockchip SoCs, such as the RK3399, suffer from a bug
> +that mandates the above-described data spreading, thus requiring the rkspi
> +format to be used for their SPI images. Rockchip SoCs that don't suffer
> +from this bug use the rksd format for their SPI images.
> +

Then I would suggest we move

"""
args = "-n", CONFIG_SYS_SOC, "-T", "rkspi";
"""

from arch/arm/dts/rockchip-u-boot.dtsi

to the SoCs -u-boot.dtsi that are impacted?

e.g.

"""
#ifdef CONFIG_SPL
&binman {
#ifdef CONFIG_ROCKCHIP_SPI_IMAGE
     simple-bin-image {
         mkimage {
             args = "-n", CONFIG_SYS_SOC, "-T", "rkspi";
         };
     };
#endif
};
#endif
"""

in arch/arm/dts/rockchip/rk3399-u-boot.dtsi

and have "rksd" in rockchip-u-boot.dtsi instead?

We can then document this rkspi type specifically for those SoCs.

Because this kinda means we're currently virtually inflating the size of 
the TPL/SPL on non-impacted SoCs for no reason whatsoever.

Cheers,
Quentin