build(psci): add build option for OS-initiated mode

Change-Id: Ie4f7b6a36926ab075ebb9c6507a3ff48ce5538fe
Signed-off-by: Wing Li <wingers@google.com>

Makefile

@@ -1114,6 +1114,7 @@ $(eval $(call assert_booleans,\
         PLAT_RSS_NOT_SUPPORTED \
         PROGRAMMABLE_RESET_ADDRESS \
         PSCI_EXTENDED_STATE_ID \
+        PSCI_OS_INIT_MODE \
         RESET_TO_BL31 \
         RESET_TO_BL31_WITH_PARAMS \
         SAVE_KEYS \
@@ -1256,6 +1257,7 @@ $(eval $(call add_defines,\
         PLAT_RSS_NOT_SUPPORTED \
         PROGRAMMABLE_RESET_ADDRESS \
         PSCI_EXTENDED_STATE_ID \
+        PSCI_OS_INIT_MODE \
         RAS_EXTENSION \
         RESET_TO_BL31 \
         RESET_TO_BL31_WITH_PARAMS \

docs/getting_started/build-options.rst

@@ -740,6 +740,9 @@ Common build options
    enabled on Arm platforms, the option ``ARM_RECOM_STATE_ID_ENC`` needs to be
    set to 1 as well.
 
+-  ``PSCI_OS_INIT_MODE``: Boolean flag to enable support for optional PSCI
+   OS-initiated mode. This option defaults to 0.
+
 -  ``RAS_EXTENSION``: Numeric value to enable Armv8.2 RAS features. RAS features
    are an optional extension for pre-Armv8.2 CPUs, but are mandatory for Armv8.2
    or later CPUs. This flag can take the values 0 to 2, to align with the

make_helpers/defaults.mk

@@ -258,6 +258,9 @@ PROGRAMMABLE_RESET_ADDRESS	:= 0
 # Flag used to choose the power state format: Extended State-ID or Original
 PSCI_EXTENDED_STATE_ID		:= 0
 
+# Enable PSCI OS-initiated mode support
+PSCI_OS_INIT_MODE		:= 0
+
 # Enable RAS support
 RAS_EXTENSION			:= 0