lm4: fix enabling RTC alarm

All hibernate register writes must wait for the WC bit.  When we're
enabling the RTC alarm, it's important to wait for the WC bit
afterwards, too, or else we could go into deep sleep before the write
to HIBIM is committed.

Also make sure that the normal hibernate() path enables the RTC alarm
if it has a timeout.  This bug wasn't noticed until the low-power idle
code called system_reset_rtc_alarm(), since before then HIBIM was
initialized to 1 and just stayed there.

BUG=chrome-os-partner:23678
BRANCH=anywhere we use low power idle (wolf/leon, too)
TEST=with hacked firmware, note that HIBIM=1 just before the wfi
     instruction in chip/lm4/clock.c

Change-Id: Ie01b106ac6a6c5894811f9a333715b22ef896f82
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/175013
Reviewed-by: Alec Berg <alecaberg@chromium.org>

0 files changed, 0 insertions, 0 deletions