From 401be9c8b961cd4fcb6e5d58200dcd06a8c246b2 Mon Sep 17 00:00:00 2001
From: Manuel Bentele
Date: Wed, 11 Nov 2020 12:31:47 +0100
Subject: [BUILD] add CMake toolchain files to cross-compile for ppc and
 aarch64

---
 README.md                             | 20 ++++++++++++++++++++
 cmake/toolchain/Aarch64LinuxGnu.cmake | 24 ++++++++++++++++++++++++
 cmake/toolchain/PowerpcLinuxGnu.cmake | 24 ++++++++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 cmake/toolchain/Aarch64LinuxGnu.cmake
 create mode 100644 cmake/toolchain/PowerpcLinuxGnu.cmake

diff --git a/README.md b/README.md
index d8e390e..a46423e 100644
--- a/README.md
+++ b/README.md
@@ -110,6 +110,26 @@ A value from the range of appropriate values can be assigend to each configurati
 cmake -D<VARIABLE>=<VALUE> [-D ...] ../.
 ```
 
+With the help of CMake, it is also possible to cross-compile the dnbd3 components for a Linux target architecture other than the compiling Linux host architecture. This repository is shipped with two CMake toolchain files to cross-compile all components for the following two Linux target architectures if necessary.
+
+> **Note that all used header files (eg. Linux kernel headers) and libraries (eg. jansson, fuse) for the target architecture are installed and set up properly, so that the cross-compiler can find and use them.**
+
+
+#### Cross-Compiling for _powerpc_ Target
+If you want to cross-compile all dnbd3 components for the _powerpc_ Linux target architecture (eg. for a Mac G5), make sure that the `powerpc-linux-gnu-gcc` cross-compiler is installed on your host system. Then, call CMake with the shipped toolchain file for this specific cross-compiler as follows.
+
+```shell
+cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchain/PowerpcLinuxGnu.cmake [-D ...] ../.
+```
+
+
+#### Cross-Compiling for _aarch64_ Target
+If you want to cross-compile all dnbd3 components for the _aarch64_ Linux target architecture (eg. for a Raspberry Pi 4), make sure that the `aarch64-linux-gnu-gcc` cross-compiler is installed on your host system. Then, call CMake with the shipped toolchain file for this specific cross-compiler as follows.
+
+```shell
+cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/toolchain/Aarch64LinuxGnu.cmake [-D ...] ../.
+```
+
 
 ### Debug
 In the `Debug` build configuration, all dnbd3 components can be built by calling `make`:
diff --git a/cmake/toolchain/Aarch64LinuxGnu.cmake b/cmake/toolchain/Aarch64LinuxGnu.cmake
new file mode 100644
index 0000000..59c5f00
--- /dev/null
+++ b/cmake/toolchain/Aarch64LinuxGnu.cmake
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# CMAKE toolchain file for cross compilation with aarch64-linux-gnu-gcc
+#
+# Copyright (C) 2020 Manuel Bentele <development@manuel-bentele.de>
+#
+
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR aarch64)
+
+set(CMAKE_C_COMPILER aarch64-linux-gnu-gcc)
+set(CMAKE_CXX_COMPILER aarch64-linux-gnu-g++)
+set(CMAKE_LINKER aarch64-linux-gnu-ld)
+set(CMAKE_ASM_COMPILER aarch64-linux-gnu-as)
+set(CMAKE_OBJCOPY aarch64-linux-gnu-objcopy)
+set(CMAKE_STRIP aarch64-linux-gnu-strip)
+set(CMAKE_CPP aarch64-linux-gnu-cpp)
+
+# path of headers and libraries for aarch64-linux-gnu target
+set(CMAKE_FIND_ROOT_PATH "/usr/aarch64-linux-gnu")
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
diff --git a/cmake/toolchain/PowerpcLinuxGnu.cmake b/cmake/toolchain/PowerpcLinuxGnu.cmake
new file mode 100644
index 0000000..d3c1ca5
--- /dev/null
+++ b/cmake/toolchain/PowerpcLinuxGnu.cmake
@@ -0,0 +1,24 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# CMAKE toolchain file for cross compilation with powerpc-linux-gnu-gcc
+#
+# Copyright (C) 2020 Manuel Bentele <development@manuel-bentele.de>
+#
+
+set(CMAKE_SYSTEM_NAME Linux)
+set(CMAKE_SYSTEM_PROCESSOR ppc)
+
+set(CMAKE_C_COMPILER powerpc-linux-gnu-gcc)
+set(CMAKE_CXX_COMPILER powerpc-linux-gnu-g++)
+set(CMAKE_LINKER powerpc-linux-gnu-ld)
+set(CMAKE_ASM_COMPILER powerpc-linux-gnu-as)
+set(CMAKE_OBJCOPY powerpc-linux-gnu-objcopy)
+set(CMAKE_STRIP powerpc-linux-gnu-strip)
+set(CMAKE_CPP powerpc-linux-gnu-cpp)
+
+# path of headers and libraries for powerpc-linux-gnu target
+set(CMAKE_FIND_ROOT_PATH "/usr/powerpc-linux-gnu")
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
-- 
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