I was able to pass the data to AES peripheral through the CSU DMA (csu_sss_cfg=0x000005a0 which means DMA to AES, AES to DMA). Once the data has been encrypted (respective bits have been updated: aes_busy - cleared, aes_ready - cleared, aes_done is set) I was expected to get encrypted data back but CSU DMA is stuck on the DST channel. It shows the busy status and its count have not been decremented at all. However DMA loopback works fine.
How could this possible that the data was disappeared?