[PATCH 4/5] tools: Add dumpfwumdata tool for FWU metadata image

[Dario Binacchi]

Hello Kory,

On Mon, Jan 12, 2026 at 10:24 AM Kory Maincent
<kory.maincent at bootlin.com> wrote:
>
> On Mon, 12 Jan 2026 10:05:50 +0100
> Michal Simek <monstr at monstr.eu> wrote:
>
> > On 1/11/26 16:17, Dario Binacchi wrote:
> > > Hello Michal,
> > >
> > > On Mon, Jan 5, 2026 at 4:40 PM Michal Simek <monstr at monstr.eu> wrote:
> > >>
> > >> ne 28. 12. 2025 v 16:19 odesílatel Dario Binacchi
> > >> <dario.binacchi at amarulasolutions.com> napsal:
> > >>>
> > >>> Allow reading FWU metadata from userspace.
> > >>>
> > >>> According to [1], after updating the software on bank B, setting
> > >>> active_index to point to it (i. e. 1) and marking it as a Valid bank, it
> > >>> must be possible to read this information from userspace on the next
> > >>> boot to verify whether the boot chain of bank B succeeded.
> > >>>
> > >>> The metadata must then be updated again, marking the bank as INVALID if
> > >>> the active_index points to bank A (i. e. 0) or as VALID if the boot was
> > >>> successful.
> > >>>
> > >>> To allow reading the active_index and bank state, this new tool has been
> > >>> added.
> > >>>
> > >>> Signed-off-by: Dario Binacchi <dario.binacchi at amarulasolutions.com>
>
> ...
>
> > >>> +}
> > >>> +
> > >>> +static int fwu_read_mdata(struct fwu_mdata *mdata, const char
> > >>> *mdata_file) +{
> > >>> +       FILE *mfile = NULL;
> > >>> +       size_t ret, size = sizeof(struct fwu_mdata);
> > >>> +
> > >>> +       mfile = fopen(mdata_file, "r");
> > >>> +       if (!mfile) {
> > >>> +               fprintf(stderr, "Error: Failed to open %s\n",
> > >>> +                       mdata_file);
> > >>> +               return -1;
> > >>> +       }
> > >>> +
> > >>> +       ret = fread(mdata, 1, size, mfile);
> > >>> +       fclose(mfile);
> > >>> +       if (ret != size) {
> > >>> +               fprintf(stderr, "Error: Failed to read from %s\n",
> > >>> +                       mdata_file);
> > >>> +               return -1;
> > >>> +       }
> > >>> +
> > >>> +       return 0;
> > >>> +}
> > >>> +
> > >>> +int main(int argc, char *argv[])
> > >>> +{
> > >>> +       int c, ret;
> > >>> +       struct fwu_mdata mdata;
> > >>> +
> > >>> +       if (argc < 3) {
> > >>> +               print_usage();
> > >>> +               return -EINVAL;
> > >>> +       }
> > >>
> > >> above you have only help and here you are asking for 3 args which
> > >> seems to me wrong.
> > >
> > > Thank you for your review and the feedback on my patch series.
> > > After I sent the series, I realized that this series had previously
> > > been posted:
> > > https://lore.kernel.org/all/20251212-feature_fwumdata-v2-0-ad51572fbe79@bootlin.com/.
> > >  From what I understand, it starts from the same need as mine, namely
> > > the implementation of a tool that
> > > allows reading FWU metadata from Linux. My version is definitely more
> > > minimal compared to what Kory
> > > has done.
> > > Therefore, before sending a v2, I think it would be useful to
> > > understand which of the two makes more sense
> > > to move forward with. Could you help me with that? I have also CCed
> > > Kory to keep the discussion shared.
> >
> > Kory's version looks more complete. If Kory is happy to send another version
> > I think you should test it, review it. If he is not going to send v3 I think
> > you should merge your series with his and send another version.
>
> Hello,
>
> I was going to ping reviews on my series.
> I will be glad to send a 3rd version but there will be no change from v2 as
> nobody reviewed it for now, but if needed I can resend it.
> It would be nice if you review and test it on you side to know if it match your
> requirements.

I'll be resuming work on swupdate for our STM32MP-based custom board shortly
and will test your series as soon as possible.

Just one question: I was expecting the introduction of a tool to read the
data contained in fwu-metadata. Why does your new tool also add write
functionality, considering that mkfwumdata already exists?

Thanks and regards,

Dario

>
> Regards,
> --
> Köry Maincent, Bootlin
> Embedded Linux and kernel engineering
> https://bootlin.com



-- 

Dario Binacchi

Senior Embedded Linux Developer

dario.binacchi at amarulasolutions.com

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