feat(fvp): enable support for PSCI OS-initiated mode

Change-Id: I4cd6d2bd7ec7f581bd525d5323a3b54e855e2e51
Signed-off-by: Wing Li <wingers@google.com>
diff --git a/plat/arm/board/fvp/fvp_pm.c b/plat/arm/board/fvp/fvp_pm.c
index 6b9d618..a85b545 100644
--- a/plat/arm/board/fvp/fvp_pm.c
+++ b/plat/arm/board/fvp/fvp_pm.c
@@ -227,7 +227,11 @@
  * FVP handler called when a power domain is about to be suspended. The
  * target_state encodes the power state that each level should transition to.
  ******************************************************************************/
+#if PSCI_OS_INIT_MODE
+static int fvp_pwr_domain_suspend(const psci_power_state_t *target_state)
+#else
 static void fvp_pwr_domain_suspend(const psci_power_state_t *target_state)
+#endif
 {
 	unsigned long mpidr;
 
@@ -237,7 +241,11 @@
 	 */
 	if (target_state->pwr_domain_state[ARM_PWR_LVL0] ==
 					ARM_LOCAL_STATE_RET)
+#if PSCI_OS_INIT_MODE
+		return PSCI_E_SUCCESS;
+#else
 		return;
+#endif
 
 	assert(target_state->pwr_domain_state[ARM_PWR_LVL0] ==
 					ARM_LOCAL_STATE_OFF);
@@ -269,6 +277,12 @@
 
 	/* Program the power controller to power off this cpu. */
 	fvp_pwrc_write_ppoffr(read_mpidr_el1());
+
+#if PSCI_OS_INIT_MODE
+	return PSCI_E_SUCCESS;
+#else
+	return;
+#endif
 }
 
 /*******************************************************************************