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

[Fabian Pflug <f.pflug@pengutronix.de>]

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

Kind regards
Fabian Pflug

> 
> Sascha