[U-Boot] tpm / measured boot in u-boot

[Stuart Yoder]

I saw Simon's write-up here: https://lwn.net/Articles/571031/, which
references TPM
and trusted boot support using the TPM.

I've started looking at the TPM support code in u-boot, and am trying
to understand
it.  Before getting too far I wanted to check if there were any
pointers anyone might
have around any documentation or material that provides more detail on what the
u-boot TPM support does and does not do.  I didn't see any .txt files in u-boot.

The supports seems oriented around using commands and scripts to
measure images.  One
specific thing I'm interested is how the u-boot script itself that takes the TPM
measurements is protected against tampering.

Also, it doesn't look like TCG compliant event logs are supported.

Thanks,
Stuart