broadwell: Add small delay before Flex Ratio reboot

Hardware / Coreboot - Duncan Laurie [chromium.org] - 26 March 2015 23:51 UTC

In order to prevent possible TPM lockout due to PLTRST assertion shortly after powering up add a small delay before the reset. This will affect cold power up only, reboot/resume/warmboot will all have the flex ratio locked already so this reset is unneeded.

BUG=chrome-os-partner:29859 BRANCH=None TEST=build and boot on samus. I tried unsuccessfully to trigger the TPM lockout, but I was not able to do that consistently without this patch so it is unknown yet whether this is 100% effective.

Original-Change-Id: Ief8c9261c0268b0f90a3022213ebd2b06633b481

542307b broadwell: Add small delay before Flex Ratio reboot
src/soc/intel/broadwell/bootblock/cpu.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

Upstream: review.coreboot.org

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