CSS: Implement support for NODE_HW_STATE

This patch implements CSS platform hook to support NODE_HW_STATE PSCI
API. The platform hook queries SCP to obtain CSS power state. Power
states returned by SCP are then converted to expected PSCI return codes.

Juno's PSCI operation structure is modified to use the CSS
implementation.

Change-Id: I4a5edac0e5895dd77b51398cbd78f934831dafc0

2 files changed, 42 insertions, 3 deletions

diff --git a/plat/arm/board/juno/juno_pm.c b/plat/arm/board/juno/juno_pm.c
index cbf994a4..c355d94d 100644
--- a/plat/arm/board/juno/juno_pm.c
+++ b/plat/arm/board/juno/juno_pm.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -88,5 +88,6 @@ const plat_psci_ops_t plat_arm_psci_pm_ops = {
 	.validate_power_state		= juno_validate_power_state,
 	.validate_ns_entrypoint		= arm_validate_ns_entrypoint,
 	.get_sys_suspend_power_state	= css_get_sys_suspend_power_state,
-	.translate_power_state_by_mpidr = juno_translate_power_state_by_mpidr
+	.translate_power_state_by_mpidr = juno_translate_power_state_by_mpidr,
+	.get_node_hw_state		= css_node_hw_state
 };
diff --git a/plat/arm/css/common/css_pm.c b/plat/arm/css/common/css_pm.c
index 801d9375..7607f617 100644
--- a/plat/arm/css/common/css_pm.c
+++ b/plat/arm/css/common/css_pm.c
@@ -299,6 +299,43 @@ void css_get_sys_suspend_power_state(psci_power_state_t *req_state)
 }
 
 /*******************************************************************************
+ * Handler to query CPU/cluster power states from SCP
+ ******************************************************************************/
+int css_node_hw_state(u_register_t mpidr, unsigned int power_level)
+{
+	int rc, element;
+	unsigned int cpu_state, cluster_state;
+
+	/*
+	 * The format of 'power_level' is implementation-defined, but 0 must
+	 * mean a CPU. We also allow 1 to denote the cluster
+	 */
+	if (power_level != ARM_PWR_LVL0 && power_level != ARM_PWR_LVL1)
+		return PSCI_E_INVALID_PARAMS;
+
+	/* Query SCP */
+	rc = scpi_get_css_power_state(mpidr, &cpu_state, &cluster_state);
+	if (rc != 0)
+		return PSCI_E_INVALID_PARAMS;
+
+	/* Map power states of CPU and cluster to expected PSCI return codes */
+	if (power_level == ARM_PWR_LVL0) {
+		/*
+		 * The CPU state returned by SCP is an 8-bit bit mask
+		 * corresponding to each CPU in the cluster
+		 */
+		element = mpidr & MPIDR_AFFLVL_MASK;
+		return CSS_CPU_PWR_STATE(cpu_state, element) ==
+			CSS_CPU_PWR_STATE_ON ? HW_ON : HW_OFF;
+	} else {
+		assert(cluster_state == CSS_CLUSTER_PWR_STATE_ON ||
+				cluster_state == CSS_CLUSTER_PWR_STATE_OFF);
+		return cluster_state == CSS_CLUSTER_PWR_STATE_ON ? HW_ON :
+			HW_OFF;
+	}
+}
+
+/*******************************************************************************
  * Export the platform handlers via plat_arm_psci_pm_ops. The ARM Standard
  * platform will take care of registering the handlers with PSCI.
  ******************************************************************************/
@@ -312,5 +349,6 @@ const plat_psci_ops_t plat_arm_psci_pm_ops = {
 	.system_off		= css_system_off,
 	.system_reset		= css_system_reset,
 	.validate_power_state	= arm_validate_power_state,
-	.validate_ns_entrypoint = arm_validate_ns_entrypoint
+	.validate_ns_entrypoint = arm_validate_ns_entrypoint,
+	.get_node_hw_state	= css_node_hw_state
 };