Caliptra version related questions

[sunguk-bin-fad]

1. If Caliptra RTL 1.1 is integrated, must ROM, FMC, RT, and libcaliptra all use version 1.1 (need to use caliptra-1.1 branch)?
   : Is it possible to use the latest version of ROM, FMC, RT, and libcaliptra? (e.g. ROM1.2, RT1.2,...)

2. If RTL 1.1 and ROM 1.1 are used, can FMC, RT, and the latest libcaliptra be used?

3. I am wondering if the reason Caliptra supports Caliptra firmware update is that FMC and RT can be updated regardless of the Caliptra RTL version. If that is not the case, what is the purpose of supporting firmware updates (hitless firmware update)?

[sunguk-bin-fad]

@jlmahowa-amd Can you answer this question? or can you add someone who can answer?

[jhand2]

Latest versions of ROM, FMC, RT, and libcaliptra will all work on 1.1 hardware.

They also work on 1.0 hardware, (we have CI to ensure backward compatibility). Although there is a feature flag on some crates for 1.0 compat.

We intend for all future 1.x firmware releases to continue to work on 1.1 hardware.

[sunguk-bin-fad]

@jhand2
Thanks for your feedback. I am wondering if ROM, FMC, RT, and libcaliptra always need to maintain the same version. For example, if I use RTL1.1 and ROM1.1, can I use FMC1.2 or the latest version? Likewise, I am curious whether similar dependencies could arise for RT or libcaliptra.