Tegra194: Enable system suspend

This patch does the following:
1. Populate the cstate info corresponding to system suspend
   and communicate it to the MCE
2. Ask for MCE's acknowledgement for entering system suspend
   and instruct MCE to get inside system suspend once
   permitted

Change-Id: I51e1910e24a7e61e36ac2d12ce271290e433e506
Signed-off-by: Tejal Kudav <tkudav@nvidia.com>
Signed-off-by: Vignesh Radhakrishnan <vigneshr@nvidia.com>

plat/nvidia/tegra/soc/t194/plat_psci_handlers.c

@@ -18,6 +18,7 @@
 #include <smmu.h>
 #include <string.h>
 #include <tegra_private.h>
+#include <t194_nvg.h>
 
 extern void prepare_core_pwr_dwn(void);
 
@@ -93,6 +94,7 @@ int tegra_soc_pwr_domain_suspend(const psci_power_state_t *target_state)
 	uint64_t smmu_ctx_base;
 #endif
 	uint32_t val;
+	mce_cstate_info_t cstate_info = { 0 };
 
 	/* get the state ID */
 	pwr_domain_state = target_state->pwr_domain_state;
@@ -131,7 +133,24 @@ int tegra_soc_pwr_domain_suspend(const psci_power_state_t *target_state)
 		tegra_smmu_save_context(0);
 #endif
 
-		/* Instruct the MCE to enter system suspend state */
+                /* Prepare for system suspend */
+                cstate_info.cluster = TEGRA_NVG_CLUSTER_CC6;
+                cstate_info.system = TEGRA_NVG_SYSTEM_SC7;
+                cstate_info.system_state_force = 1;
+                cstate_info.update_wake_mask = 1;
+                mce_update_cstate_info(&cstate_info);
+
+		do {
+			val = mce_command_handler(
+					MCE_CMD_IS_SC7_ALLOWED,
+					TEGRA_NVG_CORE_C7,
+					MCE_CORE_SLEEP_TIME_INFINITE,
+					0);
+		} while (val == 0);
+
+                /* Instruct the MCE to enter system suspend state */
+                (void)mce_command_handler(MCE_CMD_ENTER_CSTATE,
+                        TEGRA_NVG_CORE_C7, MCE_CORE_SLEEP_TIME_INFINITE, 0);
 	}
 
 	return PSCI_E_SUCCESS;