css: Ensure PSCI system off/reset is not interrupted
If there is a pending interrupt, it is possible for the AP to come out
of the final WFI before SCP has a chance to act on it. Prevent this
by disabling the GIC CPU interface before issuing a WFI.
Previously, SCP would not wait on WFI before taking an action but
would shut down the core or system regardless.
Change-Id: Ib0bcf69a515d540ed4f73c11e40ec7c863e39c92
Signed-off-by: dp-arm <dimitris.papastamos@arm.com>
diff --git a/plat/arm/css/drivers/scp/css_pm_scpi.c b/plat/arm/css/drivers/scp/css_pm_scpi.c
index e22504d..3b643e6 100644
--- a/plat/arm/css/drivers/scp/css_pm_scpi.c
+++ b/plat/arm/css/drivers/scp/css_pm_scpi.c
@@ -32,6 +32,7 @@
#include <assert.h>
#include <css_pm.h>
#include <debug.h>
+#include <plat_arm.h>
#include "../scpi/css_scpi.h"
#include "css_scp.h"
@@ -134,6 +135,12 @@
{
uint32_t response;
+ /*
+ * Disable GIC CPU interface to prevent pending interrupt
+ * from waking up the AP from WFI.
+ */
+ plat_arm_gic_cpuif_disable();
+
/* Send the power down request to the SCP */
response = scpi_sys_power_state(scpi_system_shutdown);
@@ -153,6 +160,12 @@
{
uint32_t response;
+ /*
+ * Disable GIC CPU interface to prevent pending interrupt
+ * from waking up the AP from WFI.
+ */
+ plat_arm_gic_cpuif_disable();
+
/* Send the system reset request to the SCP */
response = scpi_sys_power_state(scpi_system_reboot);
