# ###############################
# STM32 toolchain file 
# ###############################

# ----------------------------------------
# File: stm32-toolchain.cmake
# Description: Cmake file for the stm32 controllers. It has two differnt
# types of kinds things it can output. It can output or build release binaries
# or it output debug builds.
# ----------------------------------------


##################################################
# Configurable Section
##################################################

# Specify the cross-compiler
set(CROSS_TOOLCHAIN arm-none-eabi-)
set(CMAKE_SYSTEM_NAME Generic)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(DEBUG_BINARY 1)
set(CMAKE_SYSTEM_VERSION 1)


#-------------------
# MCU Setup
#-------------------

# Specify the exact Chip
#set(MCU STM32F103xx)
# set(MCU STM32F441xx)
# set(MCU STM32F446xx)
set(MCU STM32G0B1CBTx)

set(MCU_DIR inc/${MCU}/)

#set(MCU_SPEC cortex-m3)
#set(MCU_SPEC cortex-m4)
set(MCU_SPEC cortex-m0plus) # Might need to change?

set(FLOAT_SPEC "") # Use when you have no FPU.
# set(FLOAT_SPEC "-mfloat-abi=hard -mfpu=fpv4-sp-d16")

# The Startup(ASM) files
string(TOLOWER startup_${MCU}.s STARTUP_FILE_NAME)

set(STARTUP_FILE ${MCU_DIR}/Source/Templates/gcc/${STARTUP_FILE_NAME})
set(SYSTEM_FILE  ${MCU_DIR}/Source/Templates/system_stm32f4xx.c)

# Set the clock speed settings, needed when an external high speed 
# oscilator is used.
set(HSE_VAL 8000000)

# Define the linker script location
set(LINKER_SCRIPT linker.ld)

# Programmer and debugging 
#set(PROGRAMMER serialupdi)
#set(PORT /dev/ttyU0)

##################################################
# Advanced Section
##################################################

#-------------------
# General Flags
#-------------------

# "-fno-builtin"::
# "-Wall":: Enables all warnings man page line:4385 
# "-ffunction-sections":: Puts each function into it's own section
# "-fdata-sections":: Puts each data chunk into it's own section.
# "-fomit-frame-pointer"::
set(OBJECT_GEN_FLAGS " \
-fno-builtin \
-Wall \
-ffunction-sections -fdata-sections \
-fomit-frame-pointer \
" CACHE INTERNAL "Common flags for C/CXX/ASM/Linker")

#-------------------
# CFLAGS
#-------------------
set(CMAKE_C_FLAGS " \
" CACHE INTERNAL "C Compiler options")

#-------------------
# ASMFLAGS for cross
#-------------------
set(CMAKE_ASM_FLAGS " \
-x assembler-with-cpp \
" CACHE INTERNAL "ASM Compiler options")

#-------------------
# LFLAGS for cross
#-------------------

# "-Wl":: Pass option as option to the linker.
# "-Map":: Map file passed to linker(an output?)
# "--gc-sections":: linkage garbage collector, part of shrinking size.
set(CMAKE_EXE_LINKER_FLAGS " \
-Wl,-Map=${PROJECT_NAME}.map \
-Wl,--print-memory-usage \
-Wl,--gc-sections \
" CACHE INTERNAL "Linker options")

#------------------
# Debug Flags
#------------------

# "-Og":: Optimizes for debugging expirence.
# "-g":: Debugging options 
# "-gdwarf-3":: Selection of the format version 3
# "-gstrict-dwarf":: Disallow using extensions of later dwarf standards.
set(CMAKE_C_FLAGS_DEBUG "-Og -g -gdwarf-3 -gstrict-dwarf " CACHE INTERNAL "C Compiler options for debug build type")
set(CMAKE_CXX_FLAGS_DEBUG "-Og -g -gdwarf-3 -gstrict-dwarf " CACHE INTERNAL "C++ Compiler options for debug build type")
set(CMAKE_ASM_FLAGS_DEBUG "-Og -g -gdwarf-3 -gstrict-dwarf " CACHE INTERNAL "ASM Compiler options for debug build type")
set(CMAKE_EXE_LINKER_FLAGS_DEBUG "" CACHE INTERNAL "Linker options for debug build type")

#------------------
# Release Flags
#-----------------

# "-Os":: Optimizes for space.
# "-flto":: Link Time Optimization
set(CMAKE_C_FLAGS_RELEASE "-Os -flto " CACHE INTERNAL "C Compiler options for release build type")
set(CMAKE_CXX_FLAGS_RELEASE "-Os -flto " CACHE INTERNAL "C++ Compiler options for release build type")
set(CMAKE_ASM_FLAGS_RELEASE "" CACHE INTERNAL "ASM Compiler options for release build type")
set(CMAKE_EXE_LINKER_FLAGS_RELEASE "-flto " CACHE INTERNAL "Linker options for release build type")

if(DEBUG_BINARY STREQUAL "1") # -- START: Debug Binary
    # Control specific options if crosscompiling

    message(STATUS "[INFO] Cross compiling for ${MCU}")
    message(STATUS "[INFO] Startup file used is ${STARTUP_FILE}")

    # Control ARM Semihosting support
    if(NOT SEMIHOSTING)
        set(SEMIHOSTING 1)
        message(WARNING "[WARN] Semihosting support not specified: Enabling by default")
    endif()

    #-------------------
    # General Flags for cross
    #-------------------
    # "thumb":: Compressed instructions, 16bits. Using only ARM is an option
    # as well.
    # "-mcpu":: The selected and in use CPU.
    # "-mthumb":: Enable the thumb(16bit) instructions.
    # "-mthumb-interwork":: Support calling between ARM and Thumb instructions
    # "-mabi":: Generate code for the given application binary interface.
    string(APPEND OBJECT_GEN_FLAGS " \
    -mcpu=${MCU_SPEC} \
    -mthumb \
    -mthumb-interwork \
    -mabi=aapcs \
    ${FLOAT_SPEC} \
    ")
    # "aapcs":: Procedure Call Standard for Arm Architecture


    #-------------------
    # CFLAGS for cross
    #-------------------
    string(APPEND CMAKE_C_FLAGS " \
    ${OBJECT_GEN_FLAGS} \
    ")

    #-------------------
    # ASMFLAGS for cross
    #-------------------
    string(APPEND CMAKE_ASM_FLAGS " \
    ${OBJECT_GEN_FLAGS} \
    ")

    #-------------------
    # LFLAGS for cross
    #-------------------
    string(APPEND CMAKE_EXE_LINKER_FLAGS " \
    ${OBJECT_GEN_FLAGS} \
    ")

    find_file(LINKER_SCRIPT_PATH
        NAMES "${LINKER_SCRIPT}"
        PATHS
        ${CMAKE_CURRENT_LIST_DIR}
        )

    if(DEFINED LINKER_SCRIPT_PATH)
        message(STATUS "[INFO] Using linker file at ${LINKER_SCRIPT_PATH}")
        string(APPEND CMAKE_EXE_LINKER_FLAGS "-T${LINKER_SCRIPT_PATH} ")
        string(APPEND CMAKE_EXE_LINKER_FLAGS "-L${CMAKE_CURRENT_SOURCE_DIR} ")
    else()
        message(FATAL_ERROR "[ERRR] Could not find linker script ${LINKER_SCRIPT}")
    endif()

    # semihosting:: is a mechanism that enables code running on an ARM target 
    # to communicate and use the Input/Output facilities on a host computer 
    # that is running a debugger.
    if("${SEMIHOSTING}" STREQUAL "1")
        #"rdimon":: remote dispatch interface monitor
        string(APPEND CMAKE_EXE_LINKER_FLAGS "--specs=rdimon.specs -lc -lrdimon ")
    else()
        #"nosys":: systems call are stubbed out.
        string(APPEND CMAKE_EXE_LINKER_FLAGS "--specs=nosys.specs ")
    endif()

else()
    # Actual build which will go onto the board
    # AKA production build.

    ######################################################################
    # @Target: ${PROJECT_NAME}.elf
    # @Brief: Build the actual elf file of the project
    ######################################################################

    #-------------------
    # Main elf
    #-------------------
#    file(GLOB MAIN_SRC
#        "src/*.c"
#        )
#    set(SOURCES
#        ${MAIN_SRC}
#        ${STARTUP_FILE}
#        ${SYSTEM_FILE}
#        )
#    add_executable(${PROJECT_NAME}.elf
#        ${SOURCES}
#        )
#    target_include_directories(${PROJECT_NAME}.elf
#        PUBLIC
#        ${PROJECT_SOURCE_DIR}/include
#        )
#    target_link_libraries(${PROJECT_NAME}.elf
#        PUBLIC
#        rtos
#        hal
#        ${MODULES_USED}
#        )
    target_compile_definitions(${PROJECT_NAME}.elf
        PUBLIC
        ${MCU}
        HSE_VALUE=${HSE_VAL}
        SEMIHOSTING=${SEMIHOSTING}
        )

    ######################################################################
    # @Target: flash
    # @Brief: flash the release/debug elf using gdb
    ######################################################################
    add_custom_target(flash DEPENDS ${PROJECT_NAME}.elf)
    add_custom_command(TARGET flash
        #COMMAND bash "-c" "pgrep -x \"openocd\" || (echo \"Please start openocd\" && exit -1)"
        COMMAND echo "Starting GDB client and loading ${PROJECT_NAME}.elf dashboard to $(GDB_TTY)"
        COMMAND ${CMAKE_C_GDB} ${PROJECT_NAME}.elf
        -ex "target extended :3333"
        -ex "dashboard -output $(GDB_TTY)"
        -ex "load ${PROJECT_NAME}.elf"
        -ex "monitor arm semihosting enable"
        )

    # Add additional files to the make clean
    set_property(DIRECTORY PROPERTY ADDITIONAL_MAKE_CLEAN_FILES
        "${PROJECT_NAME}.map"
        "${CMAKE_CURRENT_BINARY_DIR}/html"
        "${CMAKE_CURRENT_BINARY_DIR}/latex"
        )
else()
    message(FATAL_ERROR "Given TARGET_GROUP unknown")
endif() # -- END: DEBUG/RELEASE Binary 

# Unset all cache
unset(SEMIHOSTING)
unset(CMAKE_TOOLCHAIN_FILE)
unset(CMAKE_BUILD_TYPE)