#   Part of the Raspberry-Pi Bare Metal Tutorials
#   Copyright (c) 2015, Brian Sidebotham
#   All rights reserved.

#   Redistribution and use in source and binary forms, with or without
#   modification, are permitted provided that the following conditions are met:

#   1. Redistributions of source code must retain the above copyright notice,
#       this list of conditions and the following disclaimer.

#   2. Redistributions in binary form must reproduce the above copyright notice,
#       this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.

#   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
#   AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
#   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
#   ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
#   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
#   CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
#   SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
#   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
#   CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
#   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
#   POSSIBILITY OF SUCH DAMAGE.

# CMake build environment for the Valvers Raspberry-Pi bare metal tutorials

# CMake 2.8.10 Documentation: http://www.cmake.org/cmake/help/v2.8.10/cmake.html

cmake_minimum_required( VERSION 2.8 )

# Mark the language as C so that CMake doesn't try to test the C++
# cross-compiler's ability to compile a simple program because that will fail
project( bare-metal-rpi-kernel C ASM )
enable_language(C ASM)

set( TARGET_FILE "kernel")
set( TARGET_BUILD "${TARGET_FILE}.elf")
set( TARGET_OUTPUT "${TARGET_FILE}.img")

# Add any C compiler flags here. The C flags concerned with processor tuning
# are in the toolchain files toolchain-arm-none-eabi-bcm2835.cmake, etc.
set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O4" )
set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall" )
set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -nostartfiles" )
set( CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -I src/includes/" )

# Set the linker flags so that we use our "custom" linker script
set( CMAKE_EXE_LINKER_FLAGS "-Wl,-T,src/CMakeLinker.x" )

AUX_SOURCE_DIRECTORY(src source)
AUX_SOURCE_DIRECTORY(src/includes/ kernelIncludes)
AUX_SOURCE_DIRECTORY(src/includes/rpi rpiIncludes)

add_executable( ${TARGET_BUILD}
    src/armStart.S
    ${source}
    ${kernelIncludes}
    ${rpiIncludes}
)

set_target_properties( ${TARGET_BUILD}
    PROPERTIES
    ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib"
    LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib"
    RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin"
)

get_target_property(RUNTIME_OUTPUT_DIRECTORY ${TARGET_BUILD} RUNTIME_OUTPUT_DIRECTORY)

add_custom_command(
    TARGET ${TARGET_BUILD} POST_BUILD
    COMMAND ${CMAKE_OBJCOPY} ${TARGET_BUILD} -O binary ${TARGET_OUTPUT}
    WORKING_DIRECTORY ${RUNTIME_OUTPUT_DIRECTORY}
    COMMENT "Convert the ELF output file to a binary image" )