Version armada-18.09 has been released.
An inexplicable behavior was resolved in this version(mv_ddr-devel-18.09.1).
I replaced the 4GB NonECC DIMM with a 16GB ECC DIMM two months ago.
Linux kernel was frequently logging errors since that. [ 351.562134] Synchronous External Abort: synchronous external abort (0x92000210) at 0x0000007fa4f5e6e0
After occurrence of an error,
the register MC6_CH0_ECC_1BIT_ERR_COUNTER_REG has been incremented by several hundreds or more.
It does not happen if I modify mv_ddr source to disable ECC.