feat(tc): add save/restore DSU PMU register support

This patch adds support for preserving DSU PMU registers
over a power cycle in TC platform.

These PMU registers need to be manually saved/restored
because they are part of cluster power domain and OS
doesn't know when DSU is powered OFF.

Change-Id: Ife9573f205d99d092039cb95674e7434bb5f9239
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>

plat/arm/board/tc/platform.mk

@@ -68,6 +68,9 @@ $(eval $(call add_defines, \
 
 CSS_LOAD_SCP_IMAGES	:=	1
 
+# Save DSU PMU registers on cluster off and restore them on cluster on
+PRESERVE_DSU_PMU_REGS		:= 1
+
 # Include GICv3 driver files
 include drivers/arm/gic/v3/gicv3.mk
 
@@ -128,6 +131,7 @@ BL31_SOURCES		+=	${INTERCONNECT_SOURCES}	\
 				${TC_BASE}/tc_topology.c	\
 				lib/fconf/fconf.c			\
 				lib/fconf/fconf_dyn_cfg_getter.c	\
+				drivers/arm/css/dsu/dsu.c			\
 				drivers/cfi/v2m/v2m_flash.c		\
 				lib/utils/mem_region.c			\
 				plat/arm/common/arm_nor_psci_mem_protect.c	\

plat/arm/css/common/css_pm.c

@@ -12,6 +12,7 @@
 #include <bl31/interrupt_mgmt.h>
 #include <common/debug.h>
 #include <drivers/arm/css/css_scp.h>
+#include <drivers/arm/css/dsu.h>
 #include <lib/cassert.h>
 #include <plat/arm/common/plat_arm.h>
 
@@ -82,8 +83,12 @@ static void css_pwr_domain_on_finisher_common(
 	 * Perform the common cluster specific operations i.e enable coherency
 	 * if this cluster was off.
 	 */
-	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
+	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF) {
+#if PRESERVE_DSU_PMU_REGS
+		cluster_on_dsu_pmu_context_restore();
+#endif
 		plat_arm_interconnect_enter_coherency();
+	}
 }
 
 /*******************************************************************************
@@ -131,8 +136,12 @@ static void css_power_down_common(const psci_power_state_t *target_state)
 	plat_arm_gic_cpuif_disable();
 
 	/* Cluster is to be turned off, so disable coherency */
-	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
+	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF) {
+#if PRESERVE_DSU_PMU_REGS
+		cluster_off_dsu_pmu_context_save();
+#endif
 		plat_arm_interconnect_exit_coherency();
+	}
 }
 
 /*******************************************************************************