nb/intel/x4x/raminit: Rework receive enable calibration
Moves receive enable calibration to a separate file to lighten
raminit.c a bit.
Receive enable calibration is quite similar to gm45 so it reuses some
of its function names.
The functional changes are:
* the minimum coarse is now reset for each channel;
* on the second fine search for DQS high, TAP overflow is handled by
increasing medium;
* start coarse at CAS + 1 instead of CAS - 1. Other Intel northbridges
do the same and the results are more in line with register dumps
from vendor bios.
These might improve stability.
TESTED on ga-g41m-es2l
Change-Id: I0c970455e609d3ce96a262cbf110336a2079da4d
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/18692
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
4 files changed