fix(plat/marvell/a8k): Require that MV_DDR_PATH is correctly set

Target mrvl_flash depends on external mv_ddr source code which is not
part of TF-A project. Do not expect that it is pre-downloaded at some
specific location and require user to specify correct path to mv_ddr
source code via MV_DDR_PATH build option.

TF-A code for Armada 37x0 platform also depends on mv_ddr source code
and already requires passing correct MV_DDR_PATH build option.

So for A8K implement same checks for validity of MV_DDR_PATH option as
are already used by TF-A code for Armada 37x0 platform.
Signed-off-by: Pali Rohár <pali@kernel.org>
Change-Id: I792f2bfeab0cec89b1b64e88d7b2c456e22de43a

docs/plat/marvell/armada/build.rst

@@ -129,15 +129,13 @@ There are several build options:
 
 - MV_DDR_PATH
 
+        This parameter is required for ``mrvl_flash`` and ``mrvl_uart`` targets.
+
         For A7K/8K/CN913x, use this parameter to point to mv_ddr driver sources to allow BLE build. For A37x0,
         it is used for ddr_tool build.
 
         Usage example: MV_DDR_PATH=path/to/mv_ddr
 
-        The parameter is optional for A7K/8K/CN913x, when this parameter is not set, the mv_ddr
-        sources are expected to be located at: drivers/marvell/mv_ddr. However, the parameter
-        is necessary for A37x0.
-
         For the mv_ddr source location, check the section "Tools and external components installation"
 
         If MV_DDR_PATH source code is a git snapshot then provide path to the full git

plat/marvell/armada/a8k/common/ble/ble.mk

@@ -3,8 +3,6 @@
 # SPDX-License-Identifier:     BSD-3-Clause
 # https://spdx.org/licenses
 
-MV_DDR_PATH		?=	drivers/marvell/mv_ddr
-
 MV_DDR_LIB		=	$(BUILD_PLAT)/ble/mv_ddr_lib.a
 LIBC_LIB		=	$(BUILD_PLAT)/lib/libc.a
 BLE_LIBS		=	$(MV_DDR_LIB) $(LIBC_LIB)
@@ -28,4 +26,7 @@ PLAT_INCLUDES		+= 	-I$(MV_DDR_PATH)				\
 BLE_LINKERFILE		:=	$(BLE_PATH)/ble.ld.S
 
 $(MV_DDR_LIB): FORCE
+	$(if $(value MV_DDR_PATH),,$(error "Platform '$(PLAT)' for BLE requires MV_DDR_PATH. Please set MV_DDR_PATH to point to the right directory"))
+	$(if $(wildcard $(value MV_DDR_PATH)/*),,$(error "'MV_DDR_PATH=$(value MV_DDR_PATH)' was specified, but '$(value MV_DDR_PATH)' directory does not exist"))
+	$(if $(shell git -C $(value MV_DDR_PATH) rev-parse --show-cdup 2>&1),$(error "'MV_DDR_PATH=$(value MV_DDR_PATH)' was specified, but '$(value MV_DDR_PATH)' does not contain valid mv-ddr-marvell git repository"))
 	@+make -C $(MV_DDR_PATH) --no-print-directory PLAT_INCLUDES="$(PLAT_INCLUDES)" PLATFORM=$(PLAT) ARCH=AARCH64 OBJ_DIR=$(BUILD_PLAT)/ble