[PATCH v2 1/2] scripts/Makefile.xpl: Align filtered DTB to 8-byte within multidtb.fit

[Marek Vasut]

On 1/12/26 11:03 PM, Tom Rini wrote:

>>> This we can fix in the Makefile via the dd command as suggested by Tom.
>>
>> My concern is about LEGACY fitImages (means already generated ones), not
>> newly generated ones.
> 
> Why is that a concern? If it's a legacy fitImage for the OS, we relocate
> the device tree already normally to be aligned. If it's a legacy
> fitImage of U-Boot, it's an old U-Boot?

Not necessarily, it could be new U-Boot using old fitImage, for whatever 
reason (falcon boot maybe ?). We should not break that.

>>>> - Should mkimage -E align blobs to 8 bytes by default ? I think yes,
>>>> and frankly, I thought it does so already, but apparently not.
>>>
>>>
>>> This can be done, but should it be? Not all FITs demand an 8-byte
>>> alignment right? It is only the FDT which requires this.
>> Maybe if image type is flat_dt, it should be implicitly 8-byte aligned then
>> ?
> 
> Well, the device tree spec says 8-byte alignment.

8 byte alignment of what, start of DT, right ?

> It's not "FDT for OS"
> that's 8-byte, it's any device tree should start out 8 byte aligned, and
> everything else should then be naturally aligned. If we're looking in a
> device tree for another device tree to use in place and not relocate
> then that second tree must be aligned.
> 
> Or am I missing something?
The discussion is about mkimage -E which generates DTs for U-Boot SPL 
use. The DTs in those external data should likely be aligned to 8 bytes 
by default, i.e. implicitly set -B 8 (they don't seem to be right now).