[PATCH] fdtgrep: Add option to reserve free space in the output FDT

[Simon Glass]

Hi Marek,

On Thu, 23 Apr 2026 at 07:08, Marek Vasut <marek.vasut at mailbox.org> wrote:
>
> On 4/22/26 4:31 AM, Simon Glass wrote:
> > When producing a DTB from fdtgrep, there is no way to reserve extra
> > space so that more nodes/properties can be added at runtime without
> > growing totalsize first.
> >
> > Add a -B/--pad option that appends a caller-specified number of free
> > bytes after the strings section and grows totalsize accordingly. The
> > padding is applied after fdt_pack(), so it is not reclaimed when -r is
> > used.
> >
> > Suggested-by: Marek Vasut <marek.vasut at mailbox.org>
> > Signed-off-by: Simon Glass <sjg at chromium.org>
> > ---
> >
> >   tools/binman/btool/fdtgrep.py |  3 ++-
> >   tools/fdtgrep.c               | 31 ++++++++++++++++++++++++++++++-
> >   2 files changed, 32 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/binman/btool/fdtgrep.py b/tools/binman/btool/fdtgrep.py
> > index 446b2f4144b..7b393241878 100644
> > --- a/tools/binman/btool/fdtgrep.py
> > +++ b/tools/binman/btool/fdtgrep.py
> > @@ -16,9 +16,10 @@ Output formats are:
> >       dtb - device tree blob (sets -Hmt automatically)
> >       bin - device tree fragment (may not be a valid .dtb)
> >
> > -Options: -[haAc:b:C:defg:G:HIlLmn:N:o:O:p:P:rRsStTvhV]
> > +Options: -[haAB:c:b:C:defg:G:HIlLmn:N:o:O:p:P:rRsStTvhV]
> >     -a, --show-address                 Display address
> >     -A, --colour                       Show all nodes/tags, colour those that match
> > +  -B, --pad <arg>                    Append free space to the output FDT, for later growth
> Shouldn't the parameter at least match the dtc -p parameter ? -p is not
> taken yet.

We have:

  -p, --include-prop <arg>           Property to include in grep

Regards,
Simon