C/C++ Programming

Cross compilation

1. Download SKD from .. _Mediatek downloads page: https://docs.labs.mediatek.com/resource/linkit-smart-7688/en/downloads e.g.:

   wget https://labs.mediatek.com/en/download/AGSSkG38
   

2. Unpack:

   sudo tar -xvjf SDK.tar.bz2
   

Node.js native addons cross-compilation

1. Fork the module repo

2. Clone and edit unnecessary dependencies like nan

3. Deploy SKD if needed. Set $STAGING_DIR environment variable, e.g.:

   export STAGING_DIR=/sdk/OpenWrt-SDK-ramips-mt7688_gcc-4.8-linaro_uClibc-0.9.33.2.Linux-x86_64/staging_dir
   

4. Run the following bash script in the module folder:

   set -e
   
   if [ ! -d "$STAGING_DIR" ]; then
       echo "STAGING_DIR needs to be set to your cross toolchain path";
       exit 1
   fi
   
   ARCH=${ARCH:-mipsel}
   NODE=${NODE:-0.12.7}
   
   TOOLCHAIN_DIR=$(ls -d "$STAGING_DIR/toolchain-"*)
   echo $TOOLCHAIN_DIR
   
   export SYSROOT=$(ls -d "$STAGING_DIR/target-"*)
   
   source $TOOLCHAIN_DIR/info.mk # almost a bash script
   
   echo "Cross-compiling for" $TARGET_CROSS
   
   export PATH=$TOOLCHAIN_DIR/bin:$PATH
   export CPPPATH=$TARGET_DIR/usr/include
   export LIBPATH=$TARGET_DIR/usr/lib
   
   #TODO: anything better than this hack?
   OPTS="-I $SYSROOT/usr/include -L $TOOLCHAIN_DIR/lib -L $SYSROOT/usr/lib"
   
   export CC="${TARGET_CROSS}gcc $OPTS"
   export CXX="${TARGET_CROSS}g++ $OPTS"
   export AR=${TARGET_CROSS}ar
   export RANLIB=${TARGET_CROSS}ranlib
   export LINK="${TARGET_CROSS}g++ $OPTS"
   export CPP="${TARGET_CROSS}gcc $OPTS -E"
   export STRIP=${TARGET_CROSS}strip
   export OBJCOPY=${TARGET_CROSS}objcopy
   export LD="${TARGET_CROSS}g++ $OPTS"
   export OBJDUMP=${TARGET_CROSS}objdump
   export NM=${TARGET_CROSS}nm
   export AS=${TARGET_CROSS}as
   
   export npm_config_arch=$ARCH
   node-gyp rebuild --target=$NODE -v
   

5. Remove /build from .gitignore, commit and push.

6. Install directly from GitHub, e.g.:

   npm install https://github.com/Voxiferus/node-spi.git --global