cheza: Make chipset_reset do a warm reset

Make the chipset_reset function do a warm reset to match the
expectation of what AP-initiated reset does, which is also a
warm reset but triggered by PS_HOLD.

The warm reset is done by sending a low pulse to the PMIC
RESIN_L pin, which requires PMIC registers being reprogrammed
that makes it as a warm reset trigger.

If the PMIC registers not reprogrammed properly, it falls back
to do a cold reset power sequence. It is done by EC monitoring
the AP_RST_L signal, which is already one of the power signals.

BRANCH=none
BUG=b:117941911
TEST=Typed "apreset" just after "reboot" (PMIC registers not
programmed), checked the transition S0 -> S5 -> S0.
TEST=Typed "apreset" when AP booted into userspace (PMIC
registers programmed), checked a warm reset happened, AP_RST_L
toggled.

Change-Id: Ia1c5c7a8fd56a9e4867d4dd4c8bf2333c083c616
Signed-off-by: Wai-Hong Tam <waihong@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1330117
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>

0 files changed, 0 insertions, 0 deletions