The ALTDQ_DQS2 Hard Read FIFO has the following ports as described below:
lfifo_rden: Data input to the Read FIFO Read Enable. This signal is the full read enable token generated by user logic and is asserted for the length of the desired read burst.
rfifo_reset_n: Active low reset to the Read FIFO.
vfifo_qvld: This signal is used as the write enable on the Read FIFO in all cases
where the capture strobe is not bidirectional.