rfnoc: Update the MTU forwarding property for some blocks

Note that the default MTU forwarding policy is ONE_TO_ONE, therefore,
it is only strictly necessary to modify the MTU forwarding policy for
blocks that route data in a different manner. However, it may be nice to
explicitly state the forwarding policy for the benefit of the reader.

The following blocks had their policies updated:
- addsub: ONE_TO_FAN
- duc: ONE_TO_ONE
- dmafifo: ONE_TO_ONE
- null block: DROP
- replay block: DROP
- split stream: ONE_TO_FAN
- switchboard: ONE_TO_FAN

1 files changed, 3 insertions, 0 deletions

diff --git a/host/lib/rfnoc/addsub_block_control.cpp b/host/lib/rfnoc/addsub_block_control.cpp
index 516b348b1..f91703193 100644
--- a/host/lib/rfnoc/addsub_block_control.cpp
+++ b/host/lib/rfnoc/addsub_block_control.cpp
@@ -37,6 +37,9 @@ public:
         // opposite side from which they are received.
         set_prop_forwarding_policy(forwarding_policy_t::ONE_TO_FAN);
         set_action_forwarding_policy(forwarding_policy_t::ONE_TO_FAN);
+        // MTU is also fanned out the same way as we produce output packets the
+        // same size as input packets.
+        set_mtu_forwarding_policy(forwarding_policy_t::ONE_TO_FAN);
 
         // Register the block's edge type properties.
         register_property(&_prop_type_in_a);