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

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

Hi Simon,

On 4/9/25 3:22 PM, Simon Glass wrote:
> Hi Quentin,
> 
> On Wed, 9 Apr 2025 at 04:57, Quentin Schulz <quentin.schulz@cherry.de> wrote:
>>
>> 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?
> 
> This is how binman works[1]. We are trying to use the feature designs

Why is it deducted?

Cheers,
Quentin