nb/via/cx700: Implement FSB tuning

This northbridge provides a lot of knobs for fine-grained tuning of the
FSB drivers. The programming manual calls this "Host AGTL+ I/O Driving
Control". We program the known good values for use with a VIA C7 CPU,
and warn about use with different CPUs.

The numbers were pulled out of raminit of the original CX700 port.
Originally, there was a write to 0x83 as well, to set bit 1 which
triggers a soft reset of the CPU.  It was amidst a table, so it
seems unclear if it was put there intentionally.

Change-Id: I24ba6cfaab2ca3069952a6c399a065caea7b49f2
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82769
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

0 files changed, 0 insertions, 0 deletions