4 files changed, 17 insertions, 9 deletions
diff --git a/src/soc/amd/stoneyridge/Kconfig b/src/soc/amd/stoneyridge/Kconfig
index de1cb927ab..e723296ae4 100644
--- a/src/soc/amd/stoneyridge/Kconfig
+++ b/src/soc/amd/stoneyridge/Kconfig
@@ -382,4 +382,12 @@ config DRIVERS_I2C_DESIGNWARE_CLOCK_MHZ
 	int
 	default 133
 
+config MAINBOARD_POWER_RESTORE
+	def_bool n
+	help
+	  This option determines what state to go to once power is restored
+	  after having been lost in S0.  Select this option to automatically
+	  return to S0.  Otherwise the system will remain in S5 once power
+	  is restored.
+
 endif # SOC_AMD_STONEYRIDGE_FP4 || SOC_AMD_STONEYRIDGE_FT4
diff --git a/src/soc/amd/stoneyridge/include/soc/southbridge.h b/src/soc/amd/stoneyridge/include/soc/southbridge.h
index 780a9e33d2..acdaa8a16e 100644
--- a/src/soc/amd/stoneyridge/include/soc/southbridge.h
+++ b/src/soc/amd/stoneyridge/include/soc/southbridge.h
@@ -48,6 +48,10 @@
 #define   PM_SERIRQ_MODE		BIT(6)
 #define   PM_SERIRQ_ENABLE		BIT(7)
 
+#define PM_RTC_SHADOW			0x5b	/* state when power resumes */
+#define   PM_S5_AT_POWER_RECOVERY	0x04	/* S5 */
+#define   PM_RESTORE_S0_IF_PREV_S0	0x07	/* S0 if previously at S0 */
+
 #define PM_EVT_BLK			0x60
 #define   WAK_STS			BIT(15) /*AcpiPmEvtBlkx00 Pm1Status */
 #define   PCIEXPWAK_STS			BIT(14)
diff --git a/src/soc/amd/stoneyridge/sm.c b/src/soc/amd/stoneyridge/sm.c
index 21ce75b2ef..d4f428f343 100644
--- a/src/soc/amd/stoneyridge/sm.c
+++ b/src/soc/amd/stoneyridge/sm.c
@@ -27,15 +27,6 @@
 #include <soc/southbridge.h>
 #include <soc/smbus.h>
 
-#define NMI_OFF 0
-
-#define MAINBOARD_POWER_OFF 0
-#define MAINBOARD_POWER_ON 1
-
-#ifndef CONFIG_MAINBOARD_POWER_ON_AFTER_POWER_FAIL
-#define CONFIG_MAINBOARD_POWER_ON_AFTER_POWER_FAIL MAINBOARD_POWER_ON
-#endif
-
 /*
 * The southbridge enables all USB controllers by default in SMBUS Control.
 * The southbridge enables SATA by default in SMBUS Control.
diff --git a/src/soc/amd/stoneyridge/southbridge.c b/src/soc/amd/stoneyridge/southbridge.c
index d2495a6619..57bd3f08d2 100644
--- a/src/soc/amd/stoneyridge/southbridge.c
+++ b/src/soc/amd/stoneyridge/southbridge.c
@@ -557,11 +557,16 @@ void southbridge_init(void *chip_info)
 
 void southbridge_final(void *chip_info)
 {
+	uint8_t restored_power = PM_S5_AT_POWER_RECOVERY;
+
 	if (IS_ENABLED(CONFIG_STONEYRIDGE_IMC_FWM)) {
 		agesawrapper_fchecfancontrolservice();
 		if (!IS_ENABLED(CONFIG_ACPI_ENABLE_THERMAL_ZONE))
 			enable_imc_thermal_zone();
 	}
+	if (IS_ENABLED(CONFIG_MAINBOARD_POWER_RESTORE))
+		restored_power = PM_RESTORE_S0_IF_PREV_S0;
+	pm_write8(PM_RTC_SHADOW, restored_power);
 }
 
 /*