[XS] Change in coreboot[master]: src/soc/intel/meteorlake: disable acpi timer for xtal shutdown

[Subrata Banik (Code Review)]

Attention is currently required from: Kapil Porwal, Sukumar Ghorai, Tarun Tuli.

Subrata Banik has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/75814?usp=email )

Change subject: src/soc/intel/meteorlake: disable acpi timer for xtal shutdown
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Patch Set 1:

(1 comment)

File src/soc/intel/meteorlake/fsp_params.c:

https://review.coreboot.org/c/coreboot/+/75814/comment/05d5449a_bf10d52d :
PS1, Line 619: 0
> we don't need to set this UPD.

fixing typo, we don't need to `reset` this UPD.
> Let me explain the reason why we have set this UPD.
> - Without this UPD being set, the FSP would expect to perform below operations 
>      - disable the TCO timer
>      - enable the microcode emulation timer
>
> we wanted to skip FSP-S doing those two operations hence, we have set this UPD to 1.
> disable the TCO timer: After control reaches the coreboot post FSP-S, we have disabled the TCO timer using below code
>
> https://github.com/coreboot/coreboot/blob/master/src/soc/intel/meteorlake/pm...
>
> kindly dump PMC MMIO + offset 0x18FC and check if BIT 1 is set. This will ensure that we are disabling the TCO timer.
> Enabling ucode emulation timer using https://github.com/coreboot/coreboot/blob/master/src/soc/intel/common/block/...
>
> hence, i don't believe the TCO timer is actually enabled. take a look into below output
> localhost ~ # iotools mmio_read32 0xfe0018fc
> 0x00000002