soc/intel/apollolake: Reduce D3 cold delay for eMMC controller

eMMC Controller is taking over 100ms to resume during runtime which
results in I/O latency issues on the Apollo Lake system such as Snappy.
The cause is the Linux Kernel setting the firmware reset time to
100 ms by default.

This patch adds _DSM method for eMMC comtroller for specifying the
device readiness durations. Function index 9 returns package of five
integers to set D3 cold delay to zero and ACPI constant Ones for the
elements where overriding the default values is not desired.

BUG=b:35774937
BRANCH=none
TEST=update snappy coreboot and test i/o latency is under 100ms

Signed-off-by: Zhuo-hao Lee <zhuo-hao.lee@intel.com>
Signed-off-by: Sowmya V <v.sowmya@intel.com>
Change-Id: Idcfe4252b20bead15c2e5b9cb000ff797295f06a
Reviewed-on: https://review.coreboot.org/18806
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

0 files changed, 0 insertions, 0 deletions