[PATCH] kbuild: Respect CONFIG_SYS_DTC_PAD_BYTES after fdtgrep

[Simon Glass]

Hi Marek,

On Wed, 22 Apr 2026 at 13:46, Marek Vasut <marek.vasut at mailbox.org> wrote:
>
> On 4/22/26 3:15 AM, Simon Glass wrote:
> > Hi Marek,
> >
> > On Tue, 21 Apr 2026 at 12:48, Marek Vasut <marek.vasut at mailbox.org> wrote:
> >>
> >> On 4/20/26 6:14 AM, Simon Glass wrote:
> >>> On 2026-04-20T01:23:26, Marek Vasut <marek.vasut+renesas at mailbox.org> wrote:
> >>>> kbuild: Respect CONFIG_SYS_DTC_PAD_BYTES after fdtgrep
> >>>>
> >>>> The fdtgrep command will reduce the DT to minimum size, thus eliminating
> >>>> the extra padding configured via CONFIG_SYS_DTC_PAD_BYTES. Reinstate the
> >>>> extra padding by running the output DTB from fdtgrep through DTC with the
> >>>> -p CONFIG_SYS_DTC_PAD_BYTES flag again in case CONFIG_SYS_DTC_PAD_BYTES
> >>>> is not zero.
> >>>>
> >>>> Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
> >>>>
> >>>> scripts/Makefile.lib | 7 +++++++
> >>>>    1 file changed, 7 insertions(+)
> >>>
> >>> Reviewed-by: Simon Glass <sjg at chromium.org>
> >>
> >> Is this something which can be added into fdtgrep itself btw ?
> >
> > Yes I'm sure that would be possible: perhaps a flag to maintain the
> > same padding as it finds in the input file.
> We can not determine the padding from the input DTB file itself, so the
> option would have to take a padding parameter. But I wonder if it makes
> sense to grow fdtgrep this way, or whether using dtc to reinstate the
> padding is better.

I think fdtgrep is cleaner. I'll send a patch.

Regards,
Simon