reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/wens/linux.git/commit/?id=2abb9ce9741414211f8e0a2e94cfbedc4f08e613
        git remote add wens https://git.kernel.org/pub/scm/linux/kernel/git/wens/linux.git
        git fetch --no-tags wens sunxi-wip
        git checkout 2abb9ce9741414211f8e0a2e94cfbedc4f08e613

        # install sparc64 cross compiling tool for clang build
        # apt-get install binutils-sparc64-linux-gnu
        # clang-23 might not be officially released. Try a lower version if installation fails.
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-23 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=sparc64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-23 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=sparc64 SHELL=/bin/bash drivers/mmc/host/