The command interface of a DataMover element is designed to allow command queuing. The commands are queued in a FIFO.
The command FIFO is by default a synchronous FIFO using the same clock as the memory mapped data and address channels of the associated DataMover element. However, you can specify an asynchronous command interface FIFO. This allows the command interface to be clocked at a different (generally much slower) frequency than the memory-mapped interface.