Implement PSCI_FEATURES API

This patch implements the PSCI_FEATURES function which is a mandatory
API in the PSCI 1.0 specification. A capability variable is
constructed during initialization by examining the plat_pm_ops and
spd_pm_ops exported by the platform and the Secure Payload Dispatcher.
This is used by the PSCI FEATURES function to determine which
PSCI APIs are supported by the platform.

Change-Id: I147ffc1bd5d90b469bd3cc4bbe0a20e95c247df7
diff --git a/include/bl31/services/psci.h b/include/bl31/services/psci.h
index de6fe4b..5967581 100644
--- a/include/bl31/services/psci.h
+++ b/include/bl31/services/psci.h
@@ -61,11 +61,15 @@
 #define PSCI_MIG_INFO_UP_CPU_AARCH64	0xc4000007
 #define PSCI_SYSTEM_OFF			0x84000008
 #define PSCI_SYSTEM_RESET		0x84000009
+#define PSCI_FEATURES			0x8400000A
+
+/* Macro to help build the psci capabilities bitfield */
+#define define_psci_cap(x)		(1 << (x & 0x1f))
 
 /*
  * Number of PSCI calls (above) implemented
  */
-#define PSCI_NUM_CALLS			15
+#define PSCI_NUM_CALLS			16
 
 /*******************************************************************************
  * PSCI Migrate and friends
@@ -97,6 +101,18 @@
 					PSTATE_AFF_LVL_MASK)
 
 /*******************************************************************************
+ * PSCI CPU_FEATURES feature flag specific defines
+ ******************************************************************************/
+/* Features flags for CPU SUSPEND power state parameter format. Bits [1:1] */
+#define FF_PSTATE_SHIFT		1
+#define FF_PSTATE_ORIG		0
+#define FF_PSTATE_EXTENDED	1
+
+/* Features flags for CPU SUSPEND OS Initiated mode support. Bits [0:0] */
+#define FF_MODE_SUPPORT_SHIFT		0
+#define FF_SUPPORTS_OS_INIT_MODE	1
+
+/*******************************************************************************
  * PSCI version
  ******************************************************************************/
 #define PSCI_MAJOR_VER		(0 << 16)