diff --git a/docs/porting-guide.md b/docs/porting-guide.md
index d970190..f854af9 100644
--- a/docs/porting-guide.md
+++ b/docs/porting-guide.md
@@ -150,6 +150,11 @@
     Defines the maximum number of CPUs that can be implemented within a cluster
     on the platform.
 
+*   **#define : PLATFORM_NUM_AFFS**
+
+    Defines the total number of nodes in the affinity heirarchy at all affinity
+    levels used by the platform.
+
 *   **#define : PRIMARY_CPU**
 
     Defines the `MPIDR` of the primary CPU on the platform. This value is used
diff --git a/include/bl31/services/psci.h b/include/bl31/services/psci.h
index 887c4ce..77f406d 100644
--- a/include/bl31/services/psci.h
+++ b/include/bl31/services/psci.h
@@ -128,9 +128,6 @@
 #define psci_validate_power_state(pstate) (pstate & PSTATE_VALID_MASK)
 
 
-/* Number of affinity instances whose state this psci imp. can track */
-#define PSCI_NUM_AFFS		32ull
-
 #ifndef __ASSEMBLY__
 
 #include <stdint.h>
diff --git a/plat/fvp/include/platform_def.h b/plat/fvp/include/platform_def.h
index 46a9f24..98d3004 100644
--- a/plat/fvp/include/platform_def.h
+++ b/plat/fvp/include/platform_def.h
@@ -75,6 +75,8 @@
 #define PLATFORM_CORE_COUNT		(PLATFORM_CLUSTER1_CORE_COUNT + \
 						PLATFORM_CLUSTER0_CORE_COUNT)
 #define PLATFORM_MAX_CPUS_PER_CLUSTER	4
+#define PLATFORM_NUM_AFFS		(PLATFORM_CLUSTER_COUNT + \
+					 PLATFORM_CORE_COUNT)
 #define PRIMARY_CPU			0x0
 #define MAX_IO_DEVICES			3
 #define MAX_IO_HANDLES			4
diff --git a/services/std_svc/psci/psci_private.h b/services/std_svc/psci/psci_private.h
index 08a4a34..f534087 100644
--- a/services/std_svc/psci/psci_private.h
+++ b/services/std_svc/psci/psci_private.h
@@ -33,8 +33,16 @@
 
 #include <arch.h>
 #include <bakery_lock.h>
+#include <platform_def.h>	/* for PLATFORM_NUM_AFFS */
 #include <psci.h>
 
+/* Number of affinity instances whose state this psci imp. can track */
+#ifdef PLATFORM_NUM_AFFS
+#define PSCI_NUM_AFFS		PLATFORM_NUM_AFFS
+#else
+#define PSCI_NUM_AFFS		(2 * PLATFORM_CORE_COUNT)
+#endif
+
 /*******************************************************************************
  * The following two data structures hold the topology tree which in turn tracks
  * the state of the all the affinity instances supported by the platform.