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.