Re: [PATCH v2] tlv: Add tlv_bind_soc_uid mapping

[Sascha Hauer <s.hauer@pengutronix.de>]

On Wed, Nov 19, 2025 at 04:15:40PM +0100, Jan Lübbe wrote:
> On Tue, 2025-11-18 at 10:57 +0100, Jonas Rebmann wrote:
> > Hi again, tiny addition:
> > 
> > On 2025-11-18 10:49, Jonas Rebmann wrote:
> > > On 2025-11-18 09:40, Sascha Hauer wrote:
> > > To me the big question is: What is a SoC UID?
> > > 
> > > Is it an arbitrary string that happens to be, for many SoCs composed of
> > > [0-9A-F] and efficiently represented in binary in the efuses? Then it
> > > feels a bit surprising to me to compare this 'arbitrary vendor-provided
> > > string' case-insensitively.
> > > 
> > > But if we consider this an arbitrary block of binary data, typically
> > > looked at in hexadecimal then I suggest we use the raw "bytes"-format I
> > > sent an RFC patch for on Nov 12, and compare to
> > > barebox_get_soc_uid_bin(). I originally wrote that RFC patch for storing
> > > SoC UIDs but had a conversation with Ahmad that led me to view the SoC
> > > UID as an arbitrary string. However now that we have
> > > barebox_get_soc_uid_bin(), I'm tempted to change my mind.
> > 
> > I did consider changing this for v2 however in your [PATCH v2 1/9]
> > "introduce SoC UID" you mentioned that "Others even print the binary
> > data as decimal (qcom).". If we where to use 'raw "bytes"-format' as in
> > my RFC, the data YAMLs would have hexadecimal representation and I'm not
> > sure if that could get too confusing. At least we could consider to add
> > a (mandatory?) YAML-field that specifies the number system.
> 
> As the UID is normally read from registers or messages exchanged with a security
> enclave, each SOC vendor has already defined a binary format. We should just
> store that unmodified in the TLV value instead of inventing a custom format.

The format is not custom, it's the format Linux provides in sysfs.

It might be confusing if the SOC UID we use has a different format.

Sascha

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