Re: [PATCH v2 1/2] common: misc: add soc_uid_hex to globalvar

Fabian Pflug
2026-04-22T08:53:09Z

On Wed, 2026-04-22 at 10:25 +0200, Sascha Hauer wrote:
> On Wed, Apr 22, 2026 at 10:14:11AM +0200, Fabian Pflug wrote:
> > On Wed, 2026-04-22 at 09:56 +0200, Sascha Hauer wrote:
> > > On Wed, Apr 15, 2026 at 01:10:21PM +0200, Fabian Pflug wrote:
> > > > uidstr and uidbuf could be the same, but don't have to be. This results
> > > > in uncertainty on what exactly is the current UID used for
> > > > machine_set_hashable and to compare against with TLV.
> > > >
> > > > Add an additional global var, that encodes SoC-UID registers in a
> > > > manner uniform across SoCs/manufacturers.
> > > >
> > > > This can now be used to feed as data for bound-soc-uid into
> > > > `bareboxtlv-generator.py` or as the value for
> > > > `CONFIG_HABV4_CSF_UNLOCK_UID`
> > > >
> > > > Signed-off-by: Fabian Pflug <f.pflug@pengutronix.de>
> > > > ---
> > > >  common/misc.c | 9 +++++++--
> > > >  1 file changed, 7 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/common/misc.c b/common/misc.c
> > > > index ecf9574f7a..be896706d6 100644
> > > > --- a/common/misc.c
> > > > +++ b/common/misc.c
> > > > @@ -268,6 +268,7 @@ const uuid_t *barebox_get_product_uuid(void)
> > > >  BAREBOX_MAGICVAR(global.product.uuid, "SMBIOS-reported product UUID");
> > > >
> > > >  static char *soc_uid_str;
> > > > +static char *soc_uid_bin_str;
> > > >  static void *soc_uid;
> > > >  static size_t soc_uid_len;
> > > >
> > > > @@ -295,18 +296,22 @@ void barebox_set_soc_uid(const char *uidstr, const void *uidbuf, size_t len)
> > > >   soc_uid = xmemdup(uidbuf, len);
> > > >   soc_uid_len = len;
> > > >
> > > > + soc_uid_bin_str = xzalloc(len * 2 + 1);
> > > > + bin2hex(soc_uid_bin_str, uidbuf, len);
> > > > +
> > > >   if (uidstr) {
> > > >   soc_uid_str = xstrdup(uidstr);
> > > >   } else {
> > > > - soc_uid_str = xzalloc(len * 2 + 1);
> > > > - bin2hex(soc_uid_str, uidbuf, len);
> > > > + soc_uid_str = soc_uid_bin_str;
> > > >   }
> > > >
> > > >   machine_id_set_hashable(uidbuf, len);
> > > >
> > > >   globalvar_add_simple_string("soc_uid", &soc_uid_str);
> > > > + globalvar_add_simple_string("soc_uid_hex", &soc_uid_bin_str);
> > >
> > > barebox_set_soc_uid() takes two arguments, the raw SoC UID data and a
> > > SoC specific string representation of that data. It's unfortunate that
> > > you need two different interpretations of the raw data on i.MX, one to
> > > match the Linux /sys/ format and one to put into the CSF file.
> > >
> > > Anyway, just adding a second string representation not only for i.MX,
> > > but also for all other SoCs is rather confusing. For the i.MX field
> > > return case we could also add a hab command option or a i.MX specific
> > > globalvar which is exactly described as "SoC UID in the format the CSF
> > > needs"
> >
> > Please don't get confused. This is an additional benefit for the CSF in i.MX. The main focus here is to have a
> > string
> > representation, that can be used in TLV generation, with the script in
> > https://github.com/barebox/barebox/blob/master/scripts/bareboxtlv-generator/bareboxtlv-generator.py
> >
> > The value
> > 0x0024, bound-soc-uid, "Reject TLV if supplied binary data does not match UID SoC register"
> > https://github.com/barebox/barebox/blob/v2026.04.0/common/tlv/barebox.c#L200
> >
> > Needs this representation for all vendors, not just i.MX.
> > And since the values for soc_bin and uidstr can differ greatly, it is very soc specific on what value to use in the
> > https://github.com/barebox/barebox/blob/master/scripts/bareboxtlv-generator/data-example.yaml
> >
> > This patch tries to fix it, by giving a value, that can just be copied to TLC data.yaml
>
> Ok, I can much better buy TLV support as an argument.
>
> Please add a
>
> BAREBOX_MAGICVAR(global.soc_uid_hex,
>           "byte array representation of the raw SoC UID");

There already is

BAREBOX_MAGICVAR(global.soc_uid_hex, "SoC Unique ID (in hex)");

And since it is a single value and not a byte array, I think byte array is the wrong representation.
Using a byte-array for TLV does not work with the TLV tooling. This expects a single value.

It has to be converted to a byte array for CSF, as described in the helptext for HABV4_CSF_UNLOCK_UID

Different tooling, different representation.

Fabian

>
> Sascha