[XS] Change in coreboot[main]: soc/intel/alderlake/tcss: Add definition of IOM_READY bit

[Michał Żygowski (Code Review)]

Attention is currently required from: Dinesh Gehlot, Kapil Porwal, Nick Vaccaro, Nico Huber, Subrata Banik.

Michał Żygowski has posted comments on this change by Michał Żygowski. ( https://review.coreboot.org/c/coreboot/+/83356?usp=email )

Change subject: soc/intel/alderlake/tcss: Add definition of IOM_READY bit
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Patch Set 2:

(1 comment)

Patchset:

PS1:
> Any idea where this is documented? I wonder why nobody else ran into this yet.

This is also the first time when the IOM was not ready before SiliconInit. All other TigerLake/AldeLake/RaptorLake platforms I dealt with did not have this issue.

In the ADL and RPL Core and Uncore BIOS Spec rev 0.9.2 (doc 627270) section 7.2.2.4.5 there is an information about disabling all TCSS IPs when IOM ready is not set. So, this is what FSP does here.