coreboot

Hi,
I have an Thinkpad T480 laptop and i've librebooted sucessfully but i have one weird problem that i can´t to solve it. I know T480 is not a supported device yet and @Mate Kukri is working on it, so i explained this problem in case it could be a bug to work on.

Module bios_smi of Chipsec 1.13.9 software with the prebuild libreboot rom based on coreboot fails because of TCO_Lock isn't set to 1 (it's 0), so this error is dsiplayed: "TCO SMI event configuration is not locked. TCO SMI events can be disabled".

I was analysing this error and compare the logs of chipsec execution and i realized in chipsec logs the "discovering bus configurations" with libreboot firmware didn´t find the 00:1F.4 / 8086:9D23 / Sunrise Point-LP SMBus and with stock firmware v1.52 did it. You can see in logs.

Later chipsec reads memory 00:1F.4 offset: 0x50 and:

• in stock firmware execution obtain value 0x00000401,so read this+0x8 offset obtains the TCO1_CNT register (0x1800) and bit 12 TCO_LOCK is 1 (OK)
• in librebooted firmware execution obtain value 0xFFFFFFFF (i guess because of pci device was not found)

i've reviewed configurations of menuconfig, but i didn´t know to solve it

¿Could you help please or maybe take in consideration in the work to support T480 in coreboot?
Thanks a lot!