AXI4-ST drops TREADY when traffic is started before AIB link up

[nij-intel]

This is the condition in which this issue occurs:

1. No AIB link
2. Leader drives TDATA and TVALID after axi reset
3. Follower is always TREADY = 1

Why this happens:

1. Leader side application sends data and waits for TREADY (tx_online is 0)
2. AIB links up and tx_online=1. TREADY goes high
3. AXI receives user data in FIFO and asserts FIFO full. This will de-assert TREADY
4. AXI-ST leader transmit the data to AIB through CA module asserting master_align_done=1
5. AIB leader transmits the data to AIB follower
6. CA follower module align done is still low and drops packet from AIB follower
7. AXI-ST follower does not get packet and will not send credit update to AXI-ST leader
8. AXI-ST leader is waiting for credit update from follower and waits for forever.
9. This keeps TREADY low for ever.

Work around:

Start AXI-ST traffic after AIB-link is establishes (tx_online=1)

Waveform

[nij-intel]

To reproduce this issue we had to set delay_y_value = 0

[nij-intel]

Unable to reproduce to this issue in full_examples and VIP setup. Started traffic after reset before online and TREADY is always 1

Example design delay values (in hex): X = 6, Y=1c2, Z = 190.

[nij-intel]

Better picture