reset: Log the reason for AP resets.

Provides a new EC host command 'uptime info' which gathers up some
information which may be useful for debugging spurious resets on the AP
(was the EC reset recently?  Why was the EC reset?  If the EC reset the
AP, why did it do so?, etc.).  Provide ectool support for the same.

Example results of `ectool uptimeinfo`:
```
localhost ~ # ectool uptimeinfo
EC uptime: 475.368 seconds
AP resets since EC boot: 2
Most recent AP reset causes:
	315.903: reset: console command
	363.507: reset: keyboard warm reboot
	EC reset flags at last EC boot: reset-pin | sysjump
```

BRANCH=none
TEST=Perform some `apreset` commands from the EC console and observe
their side-effects via the `ectool uptimeinfo` command on the AP side.
Test sequences include no-resets through 5 resets, observing that the
ring buffer handling was correct.

BUG=b:110788201, b:79529789
Signed-off-by: Jonathan Brandmeyer <jbrandmeyer@chromium.org>

Change-Id: I0bf29d69de471c64f905ee8aa070b15b4f34f2ba
Reviewed-on: https://chromium-review.googlesource.com/1139028
Commit-Ready: Jonathan Brandmeyer <jbrandmeyer@chromium.org>
Tested-by: Jonathan Brandmeyer <jbrandmeyer@chromium.org>
Reviewed-by: Jett Rink <jettrink@chromium.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/power/skylake.c b/power/skylake.c
index 8df01c542f..a5cf6aa0a5 100644
--- a/power/skylake.c
+++ b/power/skylake.c
@@ -23,7 +23,7 @@
 static int forcing_shutdown;  /* Forced shutdown in progress? */
 
 
-void chipset_force_shutdown(void)
+void chipset_force_shutdown(enum chipset_shutdown_reason reason)
 {
 	CPRINTS("%s()", __func__);
 
@@ -35,6 +35,7 @@ void chipset_force_shutdown(void)
 	 * hold time on the PMIC.
 	 */
 	if (!chipset_in_state(CHIPSET_STATE_ANY_OFF)) {
+		report_ap_reset(reason);
 		forcing_shutdown = 1;
 		power_button_pch_press();
 	}