Hi Sven,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on arm-perf/for-next/perf]
[also build test ERROR on linus/master v5.12-rc4 next-20210326]
[cannot apply to iommu/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Sven-Peter/Apple-M1-DART-IOMMU-driver/20210328-154437
base:   https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git for-next/perf
config: nios2-randconfig-r016-20210328 (attached as .config)
compiler: nios2-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/58778f8d813f5d98aedff621f0b236f60fe1dd2b
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Sven-Peter/Apple-M1-DART-IOMMU-driver/20210328-154437
        git checkout 58778f8d813f5d98aedff621f0b236f60fe1dd2b
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=nios2 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> nios2-linux-ld: drivers/iommu/io-pgtable.o:(.rodata+0x1c): undefined reference to `io_pgtable_apple_dart_init_fns'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org