allwinner: Allow conditional compilation of SCPI and native PSCI ops

Now that we have split the native and the SCPI version of the PSCI ops,
we can introduce build options to compile in either or both of them.

If one version is not compiled in, some stub functions make sure the
common code still compiles and makes the right decisions.

By default both version are enabled (as before), but one of them can be
disabled on the make command line, or via a platform specific Makefile.

Change-Id: I0c019d8700c0208365eacf57809fb8bc608eb9c0
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Samuel Holland <samuel@sholland.org>

plat/allwinner/common/allwinner-common.mk

 #
-# Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2017-2021, ARM Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -20,8 +20,6 @@ PLAT_BL_COMMON_SOURCES	:=	drivers/ti/uart/${ARCH}/16550_console.S	\
 				${AW_PLAT}/common/sunxi_common.c
 
 BL31_SOURCES		+=	drivers/allwinner/axp/common.c		\
-				drivers/allwinner/sunxi_msgbox.c	\
-				drivers/arm/css/scpi/css_scpi.c		\
 				${GICV2_SOURCES}			\
 				drivers/delay_timer/delay_timer.c	\
 				drivers/delay_timer/generic_delay_timer.c \
@@ -29,14 +27,40 @@ BL31_SOURCES		+=	drivers/allwinner/axp/common.c		\
 				plat/common/plat_gicv2.c		\
 				plat/common/plat_psci_common.c		\
 				${AW_PLAT}/common/sunxi_bl31_setup.c	\
-				${AW_PLAT}/common/sunxi_cpu_ops.c	\
-				${AW_PLAT}/common/sunxi_native_pm.c	\
 				${AW_PLAT}/common/sunxi_pm.c		\
-				${AW_PLAT}/common/sunxi_scpi_pm.c	\
 				${AW_PLAT}/${PLAT}/sunxi_power.c	\
 				${AW_PLAT}/common/sunxi_security.c	\
 				${AW_PLAT}/common/sunxi_topology.c
 
+# By default, attempt to use SCPI to the ARISC management processor. If SCPI
+# is not enabled or SCP firmware is not loaded, fall back to a simpler native
+# implementation that does not support CPU or system suspend.
+#
+# If SCP firmware will always be present (or absent), the unused implementation
+# can be compiled out.
+SUNXI_PSCI_USE_NATIVE	?=	1
+SUNXI_PSCI_USE_SCPI	?=	1
+
+$(eval $(call assert_boolean,SUNXI_PSCI_USE_NATIVE))
+$(eval $(call assert_boolean,SUNXI_PSCI_USE_SCPI))
+$(eval $(call add_define,SUNXI_PSCI_USE_NATIVE))
+$(eval $(call add_define,SUNXI_PSCI_USE_SCPI))
+
+ifeq (${SUNXI_PSCI_USE_NATIVE}${SUNXI_PSCI_USE_SCPI},00)
+$(error "At least one of SCPI or native PSCI ops must be enabled")
+endif
+
+ifeq (${SUNXI_PSCI_USE_NATIVE},1)
+BL31_SOURCES		+=	${AW_PLAT}/common/sunxi_cpu_ops.c	\
+				${AW_PLAT}/common/sunxi_native_pm.c
+endif
+
+ifeq (${SUNXI_PSCI_USE_SCPI},1)
+BL31_SOURCES		+=	drivers/allwinner/sunxi_msgbox.c	\
+				drivers/arm/css/scpi/css_scpi.c		\
+				${AW_PLAT}/common/sunxi_scpi_pm.c
+endif
+
 # The bootloader is guaranteed to only run on CPU 0 by the boot ROM.
 COLD_BOOT_SINGLE_CPU		:=	1
 

plat/allwinner/common/include/sunxi_private.h

@@ -16,8 +16,21 @@ void sunxi_cpu_power_off_others(void);
 void sunxi_cpu_power_off_self(void);
 void sunxi_power_down(void);
 
+#if SUNXI_PSCI_USE_NATIVE
 void sunxi_set_native_psci_ops(const plat_psci_ops_t **psci_ops);
+#else
+static inline void sunxi_set_native_psci_ops(const plat_psci_ops_t **psci_ops)
+{
+}
+#endif
+#if SUNXI_PSCI_USE_SCPI
 int sunxi_set_scpi_psci_ops(const plat_psci_ops_t **psci_ops);
+#else
+static inline int sunxi_set_scpi_psci_ops(const plat_psci_ops_t **psci_ops)
+{
+	return -1;
+}
+#endif
 int sunxi_validate_ns_entrypoint(uintptr_t ns_entrypoint);
 
 int sunxi_pmic_setup(uint16_t socid, const void *fdt);