Re: [PATCH v2] tlv: Add tlv_bind_soc_uid mapping

["Jan Lübbe" <jlu@pengutronix.de>]

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.

In the schema yaml file, we could freely define how a "bytes" format is
translated from and to a human readable representation, by adding an "text-
encoding" property (e.g. "hex-lower"/"hex-upper"/"base64") as fits each use-
case.

Jan
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