diff --git a/tools/build_system/cpu.mk b/tools/build_system/cpu.mk
index 006702f1727611db01036e6b5cea5e2309552cae..6055dd50a0d62a29f8f2fb00ffd71376e92a839e 100644
--- a/tools/build_system/cpu.mk
+++ b/tools/build_system/cpu.mk
@@ -10,12 +10,12 @@ BS_CPU_MK := 1
 
 include $(BS_DIR)/defs.mk
 
-BS_ARCH_CPU := $(BS_FIRMWARE_CPU)
-
 # Supported ARMv7-M CPUs
 ARMV7M_CPUS := cortex-m3 cortex-m7
 
 ifneq ($(findstring $(BS_FIRMWARE_CPU),$(ARMV7M_CPUS)),)
+    BS_ARCH_CPU := $(BS_FIRMWARE_CPU)
+
     BS_ARCH_ARCH := armv7-m
     BS_ARCH_ISA := thumb
 
@@ -27,7 +27,13 @@ ifneq ($(findstring $(BS_FIRMWARE_CPU),$(ARMV7M_CPUS)),)
     CFLAGS += -mno-unaligned-access # Disable unaligned access code generation
 else ifeq ($(BS_FIRMWARE_CPU),host)
     BS_ARCH_ARCH := host
+else ifeq ($(BS_FIRMWARE_CPU),optee)
+    BS_ARCH_ARCH := optee
 
+    ifeq ($(BS_ARCH_CPU),cortex-a7)
+    CFLAGS += -mfloat-abi=soft # No hardware floating point support
+    CFLAGS += -mthumb -mthumb-interwork -fno-short-enums -fno-common -mno-unaligned-access
+    endif
 else
     $(erro "$(BS_FIRMWARE_CPU) is not a supported CPU. Aborting...")
 endif
diff --git a/tools/build_system/lib-firmware.mk b/tools/build_system/lib-firmware.mk
new file mode 100644
index 0000000000000000000000000000000000000000..aba8b2d7bfe9ee47128c712cdfc6701e74072098
--- /dev/null
+++ b/tools/build_system/lib-firmware.mk
@@ -0,0 +1,294 @@
+#
+# Arm SCP/MCP Software
+# Copyright (c) 2015-2019, Arm Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+ifndef BS_FIRMWARE_MK
+BS_FIRMWARE_MK := 1
+
+include $(BS_DIR)/defs.mk
+include $(BS_DIR)/toolchain.mk
+
+$(info == Building firmware $(FIRMWARE))
+
+#
+# Validate that all mandatory definitions are defined
+#
+ifeq ($(BS_FIRMWARE_CPU),)
+    $(error "You must define BS_FIRMWARE_CPU. Aborting...")
+endif
+
+ifeq ($(BS_FIRMWARE_HAS_MULTITHREADING),)
+    $(error "You must define BS_FIRMWARE_HAS_MULTITHREADING. \
+             Valid options are: 'yes' and 'no'. \
+             Aborting...")
+endif
+
+ifeq ($(BS_FIRMWARE_HAS_NOTIFICATION),)
+    $(error "You must define BS_FIRMWARE_HAS_NOTIFICATION. \
+             Valid options are: 'yes' and 'no'. \
+             Aborting...")
+endif
+
+ifneq ($(filter-out yes no,$(BS_FIRMWARE_HAS_MULTITHREADING)),)
+    $(error "Invalid parameter for BS_FIRMWARE_HAS_MULTITHREADING. \
+             Valid options are: 'yes' and 'no'. \
+             Aborting...")
+endif
+
+ifneq ($(filter-out yes no,$(BS_FIRMWARE_HAS_NOTIFICATION)),)
+    $(error "Invalid parameter for BS_FIRMWARE_HAS_NOTIFICATION. \
+             Valid options are: 'yes' and 'no'. \
+             Aborting...")
+endif
+
+export BS_FIRMWARE_CPU
+export BS_FIRMWARE_HAS_MULTITHREADING
+export BS_FIRMWARE_HAS_NOTIFICATION
+
+#
+# Generate FIRMWARE_MODULES_LIST and list of excluded APIs for each module in
+# the following format:
+#
+# <MODULE_NAME>_DISABLED_APIS = <API_1> <API_2> ...
+#
+# NOTE: <MODULE_NAME> and <API_n> are all in uppercase
+#
+SPLIT_INPUT = $(subst $(comma), ,$(1))
+GET_MODULE_NAME = $(word 1,$(SPLIT_INPUT))
+
+define process_module_entry
+    export $(call to_upper,$(GET_MODULE_NAME))_DISABLED_APIS = \
+    $(call to_upper,$(filter-out $(GET_MODULE_NAME),$(SPLIT_INPUT)))
+
+    FIRMWARE_MODULES_LIST += $(GET_MODULE_NAME)
+    DEFINES += BUILD_HAS_MOD_$(call to_upper,$(GET_MODULE_NAME))=1
+endef
+
+$(foreach entry, \
+          $(BS_FIRMWARE_MODULES), \
+          $(eval $(call process_module_entry, $(entry))))
+
+include $(BS_DIR)/cpu.mk
+
+BUILD_PRODUCT_DIR := $(BUILD_DIR)/product/$(PRODUCT)
+BUILD_FIRMWARE_DIR := $(BUILD_PRODUCT_DIR)/$(FIRMWARE)
+BIN_DIR := $(BUILD_FIRMWARE_DIR)/$(MODE)/bin
+OBJ_DIR := $(BUILD_FIRMWARE_DIR)/$(MODE)/obj
+PRODUCT_MODULES_DIR := $(PRODUCT_DIR)/module
+FIRMWARE_DIR := $(PRODUCT_DIR)/$(FIRMWARE)
+
+TARGET := $(BIN_DIR)/$(FIRMWARE)
+TARGET_BIN := $(TARGET).bin
+TARGET_ELF := $(TARGET).elf
+
+vpath %.c $(FIRMWARE_DIR)
+vpath %.S $(FIRMWARE_DIR)
+vpath %.c $(PRODUCT_DIR)/src
+vpath %.S $(PRODUCT_DIR)/src
+
+goal: $(TARGET_ELF)
+
+ifneq ($(BS_ARCH_CPU),host)
+ifneq ($(BS_ARCH_ARCH),optee)
+    ifeq ($(BS_LINKER),ARM)
+        SCATTER_SRC = $(ARCH_DIR)/src/$(BS_ARCH_ARCH)/scatter.S
+    else
+        SCATTER_SRC = $(ARCH_DIR)/src/$(BS_ARCH_ARCH)/ld.S
+    endif
+
+    SCATTER_PP = $(OBJ_DIR)/ld_preproc.s
+endif
+endif
+
+#
+# Sources
+#
+SOURCES = $(BS_FIRMWARE_SOURCES)
+
+#
+# Modules
+#
+ALL_STANDARD_MODULES := $(patsubst $(MODULES_DIR)/%,%, \
+    $(wildcard $(MODULES_DIR)/*))
+ALL_PRODUCT_MODULES := $(patsubst $(PRODUCT_MODULES_DIR)/%,%, \
+    $(wildcard $(PRODUCT_MODULES_DIR)/*))
+
+# Check for conflicts between module names
+CONFLICTING_MODULES := $(filter $(ALL_PRODUCT_MODULES), $(ALL_STANDARD_MODULES))
+ifneq ($(CONFLICTING_MODULES),)
+    $(error "The following module(s) in '$(PRODUCT)' conflict with modules of \
+             the same name in $(MODULES_DIR): $(CONFLICTING_MODULES). \
+             Aborting...")
+endif
+
+# Check for missing or invalid modules
+MISSING_MODULES := $(filter-out $(ALL_STANDARD_MODULES) $(ALL_PRODUCT_MODULES),\
+                   $(FIRMWARE_MODULES_LIST) $(BS_FIRMWARE_MODULE_HEADERS_ONLY))
+ifneq ($(MISSING_MODULES),)
+    $(error "Missing or invalid module(s): $(MISSING_MODULES). Aborting...")
+endif
+
+# Collect both the product and non product-specific module directory paths
+MODULE_PATHS := $(wildcard $(MODULES_DIR)/* $(PRODUCT_MODULES_DIR)/*)
+
+# Filter out the module src/lib directory paths
+SOURCE_MODULE_PATHS := $(wildcard $(addsuffix /src,$(MODULE_PATHS)))
+LIBRARY_MODULE_PATHS := $(wildcard $(addsuffix /lib,$(MODULE_PATHS)))
+
+# Pull the module names from the module source directory paths
+SOURCE_MODULES := \
+    $(patsubst $(MODULES_DIR)/%/src,%,$(SOURCE_MODULE_PATHS))
+SOURCE_MODULES := \
+    $(patsubst $(PRODUCT_MODULES_DIR)/%/src,%,$(SOURCE_MODULES))
+
+# Select the source modules for the current firmware
+SOURCE_MODULES := $(filter $(FIRMWARE_MODULES_LIST),$(SOURCE_MODULES))
+
+# Pull the module names from the module library directory paths
+LIBRARY_MODULES := \
+    $(patsubst $(MODULES_DIR)/%/lib,%,$(LIBRARY_MODULE_PATHS))
+LIBRARY_MODULES := \
+    $(patsubst $(PRODUCT_MODULES_DIR)/%/lib,%,$(LIBRARY_MODULES))
+
+# Prefer sources over pre-built libraries for modules that provide both
+LIBRARY_MODULES := \
+    $(filter-out $(SOURCE_MODULES),$(LIBRARY_MODULES))
+
+# Select the library modules for the current firmware
+LIBRARY_MODULES := $(filter $(FIRMWARE_MODULES_LIST),$(LIBRARY_MODULES))
+
+# Divide libraries into two groups
+LIBRARY_MODULES_STANDARD := $(filter $(LIBRARY_MODULES),$(ALL_STANDARD_MODULES))
+LIBRARY_MODULES_PRODUCT := $(filter $(LIBRARY_MODULES),$(ALL_PRODUCT_MODULES))
+
+# Modules selected to be built into the firmware
+BUILD_STANDARD_MODULES := $(filter $(ALL_STANDARD_MODULES), \
+                                   $(SOURCE_MODULES))
+BUILD_PRODUCT_MODULES := $(filter $(ALL_PRODUCT_MODULES), \
+                                  $(SOURCE_MODULES))
+
+# Module selected to have their headers made available for inclusion by other
+# modules and their configuration files. These modules are not built into the
+# firmware.
+HEADER_STANDARD_MODULES := $(filter $(BS_FIRMWARE_MODULE_HEADERS_ONLY), \
+                                    $(ALL_STANDARD_MODULES))
+HEADER_PRODUCT_MODULES := $(filter $(BS_FIRMWARE_MODULE_HEADERS_ONLY), \
+                                   $(ALL_PRODUCT_MODULES))
+
+ifeq ($(BS_FIRMWARE_HAS_MULTITHREADING),yes)
+    BUILD_SUFFIX := $(MULTHREADING_SUFFIX)
+    BUILD_HAS_MULTITHREADING := yes
+
+    ifneq ($(BS_ARCH_ARCH),host)
+        ifeq ($(BS_COMPILER),ARM)
+            LIBS_y += $(OS_DIR)/RTX/Library/ARM/RTX_CM3.lib
+        else
+            LIBS_y += $(OS_DIR)/RTX/Library/GCC/libRTX_CM3.a
+        endif
+    endif
+
+    INCLUDES += $(OS_DIR)/RTX/Source
+    INCLUDES += $(OS_DIR)/RTX/Include
+    INCLUDES += $(OS_DIR)/../Core/Include
+else
+    BUILD_HAS_MULTITHREADING := no
+endif
+export BUILD_HAS_MULTITHREADING
+
+ifeq ($(BS_FIRMWARE_HAS_NOTIFICATION),yes)
+    BUILD_SUFFIX := $(BUILD_SUFFIX)$(NOTIFICATION_SUFFIX)
+    BUILD_HAS_NOTIFICATION := yes
+else
+    BUILD_HAS_NOTIFICATION := no
+endif
+export BUILD_HAS_NOTIFICATION
+
+# Add directories to the list of targets to build
+LIB_TARGETS_y += $(patsubst %,$(MODULES_DIR)/%/src, \
+                            $(BUILD_STANDARD_MODULES))
+LIB_TARGETS_y += $(patsubst %,$(PRODUCT_MODULES_DIR)/%/src, \
+                            $(BUILD_PRODUCT_MODULES))
+
+# Add lib path to the list of modules to link
+MODULE_LIBS_y += $(patsubst %, \
+    $(BUILD_FIRMWARE_DIR)/module/%$(BUILD_SUFFIX)/$(MODE)/lib/lib.a, \
+    $(BUILD_STANDARD_MODULES) $(BUILD_PRODUCT_MODULES))
+
+# Add path for libraries
+MODULE_LIBS_y += $(foreach module,$(LIBRARY_MODULES_STANDARD), \
+    $(MODULES_DIR)/$(module)/lib/mod_$(module).a)
+MODULE_LIBS_y += $(foreach module,$(LIBRARY_MODULES_PRODUCT), \
+    $(PRODUCT_MODULES_DIR)/$(module)/lib/mod_$(module).a)
+
+# Create a list of include directories from the selected modules and libraries
+MODULE_INCLUDES += $(patsubst %,$(MODULES_DIR)/%/include, \
+                              $(BUILD_STANDARD_MODULES) \
+                              $(LIBRARY_MODULES_STANDARD))
+MODULE_INCLUDES += $(patsubst %,$(PRODUCT_MODULES_DIR)/%/include, \
+                              $(BUILD_PRODUCT_MODULES) \
+                              $(LIBRARY_MODULES_PRODUCT))
+MODULE_INCLUDES += $(patsubst %,$(MODULES_DIR)/%/include, \
+                              $(HEADER_STANDARD_MODULES))
+MODULE_INCLUDES += $(patsubst %,$(PRODUCT_MODULES_DIR)/%/include, \
+                              $(HEADER_PRODUCT_MODULES))
+
+# Default product include directories
+PRODUCT_INCLUDES += $(PRODUCT_DIR)
+PRODUCT_INCLUDES += $(PRODUCT_DIR)/include
+
+# Add the firmware directory to the main INCLUDES list
+INCLUDES += $(FIRMWARE_DIR)
+
+# Add module, product and library includes to the main INCLUDES list
+export INCLUDES += $(MODULE_INCLUDES) $(PRODUCT_INCLUDES)
+
+#
+# Standard libraries
+#
+LIB_TARGETS_y += $(ARCH_DIR)/src
+LIB_TARGETS_y += $(FWK_DIR)/src
+
+LIBS_y += $(call lib_path,arch$(BUILD_SUFFIX))
+LIBS_y += $(call lib_path,framework$(BUILD_SUFFIX))
+
+SOURCES += $(BUILD_FIRMWARE_DIR)/fwk_module_list.c
+$(BUILD_FIRMWARE_DIR)/fwk_module_list.c: gen_module
+EXTRA_DEP := gen_module
+export EXTRA_DEP
+export BUILD_FIRMWARE_DIR
+export FIRMWARE_MODULES_LIST
+export DEFINES
+
+include $(BS_DIR)/rules.mk
+
+LDFLAGS_GCC += -Wl,-Map=$(TARGET).map
+
+ifneq ($(BS_ARCH_CPU),host)
+    LDFLAGS_GCC += -Wl,-n
+endif
+
+LDFLAGS_GCC +=  \
+    -Wl,--start-group \
+        $(BUILTIN_LIBS) \
+        $(MODULE_LIBS_y) \
+        $(LIBS_y) \
+        $(OBJECTS) \
+    -Wl,--end-group
+
+LDFLAGS_ARM += \
+    $(BUILTIN_LIBS) \
+    $(MODULE_LIBS) \
+    $(MODULE_LIBS_y) \
+    $(LIBS_y) \
+    $(OBJECTS)
+
+.SECONDEXPANSION:
+
+$(TARGET_ELF): $(LIB_TARGETS_y) $(SCATTER_PP) $(OBJECTS) | $$(@D)/
+	$(call show-action,LD,$@)
+	echo $(MODULE_LIBS_y) $(LIBS_y) $(OBJECTS) > $(BUILD_FIRMWARE_DIR)/obj-list.txt
+
+endif
diff --git a/tools/build_system/rules.mk b/tools/build_system/rules.mk
index 573170b6890d96ce1c60d6bf99513ac11856b799..debf79e1b1aba98bfaef973d177eb51217182da0 100644
--- a/tools/build_system/rules.mk
+++ b/tools/build_system/rules.mk
@@ -63,10 +63,18 @@ else
     LDFLAGS_ARM += -Wl,--scatter=$(SCATTER_PP)
     LDFLAGS_GCC += -Wl,--script=$(SCATTER_PP)
 
-    CFLAGS_GCC  += -mcpu=$(BS_ARCH_CPU)
-    ASFLAGS_GCC += -mcpu=$(BS_ARCH_CPU)
-    LDFLAGS_GCC += -mcpu=$(BS_ARCH_CPU)
-    LDFLAGS_ARM += -mcpu=$(BS_ARCH_CPU)
+    ifeq ($(BS_ARCH_CPU),cortex-a53)
+    COMMON_FLAGS := -march=armv8-a -mtune=$(BS_ARCH_CPU)
+    else ifeq ($(BS_ARCH_CPU),cortex-a7)
+    COMMON_FLAGS := -mcpu=$(BS_ARCH_CPU)
+    else
+    COMMON_FLAGS := -mcpu=$(BS_ARCH_CPU)
+    endif
+
+    CFLAGS_GCC  += $(COMMON_FLAGS)
+    ASFLAGS_GCC += $(COMMON_FLAGS)
+    LDFLAGS_GCC += $(COMMON_FLAGS)
+    LDFLAGS_ARM += $(COMMON_FLAGS)
 
     # Optional ISA ("sub-arch") parameter
     ifneq ($(BS_ARCH_ISA),)
@@ -77,6 +85,10 @@ else
     endif
 endif
 
+ifeq ($(BS_ARCH_ARCH),optee)
+    DEFINES += BUILD_OPTEE
+endif
+
 #
 # Warning flags
 #