core: arm: sm: add PSCI system suspend

Add __weak property for the function, developers
could have their own implementation.

Signed-off-by: Joseph Chen <chenjh@rock-chips.com>
Acked-by: Jerome Forissier <jerome.forissier@linaro.org>
Acked-by: Etienne Carriere <etienne.carriere@linaro.org>

core/arch/arm/include/sm/psci.h

@@ -55,6 +55,7 @@ void psci_system_off(void);
 void psci_system_reset(void);
 int psci_features(uint32_t psci_fid);
 int psci_node_hw_state(uint32_t cpu_id, uint32_t power_level);
+int psci_system_suspend(uintptr_t entry, uint32_t context_id);
 int psci_stat_residency(uint32_t cpu_id, uint32_t power_state);
 int psci_stat_count(uint32_t cpu_id, uint32_t power_state);
 void tee_psci_handler(struct thread_smc_args *args);

core/arch/arm/sm/psci.c

@@ -99,6 +99,12 @@ __weak int psci_node_hw_state(uint32_t cpu_id __unused,
 	return PSCI_RET_NOT_SUPPORTED;
 }
 
+__weak int psci_system_suspend(uintptr_t entry __unused,
+			       uint32_t context_id __unused)
+{
+	return PSCI_RET_NOT_SUPPORTED;
+}
+
 __weak int psci_stat_residency(uint32_t cpu_id __unused,
 			       uint32_t power_state __unused)
 {
@@ -159,6 +165,9 @@ void tee_psci_handler(struct thread_smc_args *args)
 	case PSCI_NODE_HW_STATE:
 		args->a0 = psci_node_hw_state(a1, a2);
 		break;
+	case PSCI_SYSTEM_SUSPEND:
+		args->a0 = psci_system_suspend(a1, a2);
+		break;
 	default:
 		args->a0 = OPTEE_SMC_RETURN_UNKNOWN_FUNCTION;
 		break;