soc/intel/cannonlake: Add _DSM method for SD controller

The SD controller seems to take some time after restarting
the clock at 1.8V before it actually switches from 3.3V to
1.8V. Add a _DSM method that simply sleeps when switching
between 3.3V and 1.8V. Otherwise, the kernel times out too
quickly waiting for the card to acknowledge the 1.8V switch.
The card itself is waiting until it sees the clk signal being
driven at 1.8V.

BUG=b:125441242
TEST=Boot Hatch with SD card and CR2 removed, observe voltage
switch succeeds.

Change-Id: I15090ed9f9bc90b35dfcba47c913e3d37b799d0b
Signed-off-by: V Sowmya <v.sowmya@intel.com>
Signef-off-by: Evan Green <evgreen@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33233
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

0 files changed, 0 insertions, 0 deletions