Hi Oleksij,

I love your patch! Yet something to improve:

[auto build test ERROR on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Oleksij-Rempel/provide-basic-selftest-support-for-the-ethernet-FEC-driver/20210330-215711
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git d0922bf7981799fd86e248de330fb4152399d6c2
config: arm64-randconfig-r012-20210330 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 482283042f795ecc27838a3b2f76b5494991401c)
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
        # install arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://github.com/0day-ci/linux/commit/80875535f65f814de8c63762039c8842a653d1e4
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Oleksij-Rempel/provide-basic-selftest-support-for-the-ethernet-FEC-driver/20210330-215711
        git checkout 80875535f65f814de8c63762039c8842a653d1e4
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 

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 >>):

>> ld.lld: error: undefined symbol: ip_send_check
   >>> referenced by fec_selftests.c
   >>> net/ethernet/freescale/fec_selftests.o:(__fec_test_loopback) in archive drivers/built-in.a
--
>> ld.lld: error: undefined symbol: udp4_hwcsum
   >>> referenced by fec_selftests.c
   >>> net/ethernet/freescale/fec_selftests.o:(__fec_test_loopback) in archive drivers/built-in.a

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