From 97e0a65081fe8043550a46e38f86481619f49c74 Mon Sep 17 00:00:00 2001
From: Furquan Shaikh <furquan@google.com>
Date: Thu, 18 Aug 2016 21:42:36 -0700
Subject: [PATCH] intel/skylake: Do not halt in poweroff if in SMM

Calling halt in poweroff when in SMM prevents SLP_SMI to be triggered
preventing the system from entering sleep state. Fix this by calling
halt only if ENV_SMM is not true.

BUG=chrome-os-partner:56395

Change-Id: I3addc1ea065346fbc5dbec9d1ad49bbd0ae05696
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/16259
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
---
 src/soc/intel/skylake/pmutil.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/soc/intel/skylake/pmutil.c b/src/soc/intel/skylake/pmutil.c
index 807579d8e0..31de242752 100644
--- a/src/soc/intel/skylake/pmutil.c
+++ b/src/soc/intel/skylake/pmutil.c
@@ -25,6 +25,7 @@
 #include <device/pci_def.h>
 #include <console/console.h>
 #include <halt.h>
+#include <rules.h>
 #include <stdlib.h>
 #include <soc/gpio.h>
 #include <soc/iomap.h>
@@ -435,5 +436,12 @@ uint16_t smbus_tco_regs(void)
 void poweroff(void)
 {
 	enable_pm1_control(SLP_EN | (SLP_TYP_S5 << SLP_TYP_SHIFT));
-	halt();
+
+	/*
+	 * Setting SLP_TYP_S5 in PM1 triggers SLP_SMI, which is handled by SMM
+	 * to transition to S5 state. If halt is called in SMM, then it prevents
+	 * the SMI handler from being triggered and system never enters S5.
+	 */
+	if (!ENV_SMM)
+		halt();
 }