[PATCH] mkimage: fit: align DTs in external data to 8 Bytes by default

[Marek Vasut]

On 1/31/26 12:14 AM, David Lechner wrote:
> On 1/28/26 9:53 PM, Marek Vasut wrote:
>> Unless specified otherwise using the mkimage -B n option, align
>> DTs in fitImage external data to 8 Bytes, and retain alignment
>> of everything else to 4 Bytes. This should fulfill the DTspec
>> requirement, that DTs must be placed at 8 Byte aligned addresses,
>> even for DTs that are part of fitImage with external data. For
>> fitImage with embedded data, there is nothing we can do, as the
>> embedded data are aligned to 4 Bytes, just like any other DT
>> property.
> 
> Could we fail with an error that tells the user they must use the
> -E option for dtbs? Or at least emitting a warning would be better
> than nothing.

Or make -E the default outright and drop support for embedded data ?

> Not for this patch but for broader discussion, it sounds like a
> `/align/ 8` could be useful in the devicetree syntax similar to
> how we have `/bits/ 8|16|32|64` already. This could (eventually)
> solve the "nothing we can do for embedded data" problem.
This would have to be DTC syntax sugar. How would that be translated 
into the DTB encoding ? In any case, this directive is something to 
discuss with the DT compiler people.