From b17220a36d0728ed4ec9bafd0ed7bef3428b9770 Mon Sep 17 00:00:00 2001
From: Fischer Moseley <42497969+fischermoseley@users.noreply.github.com>
Date: Sun, 11 Jan 2026 20:25:54 -0700
Subject: [PATCH] ethernet: fix bug where single-length write request does not
 send response

---
 src/manta/ethernet/bridge.py | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/manta/ethernet/bridge.py b/src/manta/ethernet/bridge.py
index 223780e..2aab2cb 100644
--- a/src/manta/ethernet/bridge.py
+++ b/src/manta/ethernet/bridge.py
@@ -138,13 +138,14 @@ class EthernetBridge(Elaboratable):
                     m.d.sync += self.bus_o.last.eq(self.last_i)
 
                     with m.If(self.last_i):
-                        m.next = "IDLE"  # TODO: could save a cycle by checking valid_i to see if there's more work to do
+                        m.d.sync += self.ready_o.eq(0)
+                        m.next = "WRITE_WAIT_FOR_LAST"
 
                     with m.Else():
                         m.next = "WRITE"
 
             with m.State("WRITE"):
-                with m.If(self.valid_i & self.ready_o):
+                with m.If(self.valid_i):
                     m.d.sync += self.bus_o.addr.eq(self.bus_o.addr + 1)
                     m.d.sync += self.bus_o.data.eq(self.data_i)
                     m.d.sync += self.bus_o.rw.eq(1)
@@ -153,9 +154,16 @@ class EthernetBridge(Elaboratable):
 
                     with m.If(self.last_i):
                         m.d.sync += self.ready_o.eq(0)
+                        m.next = "WRITE_WAIT_FOR_LAST"
+
+                    with m.Else():
+                        m.next = "WRITE"
 
                 with m.Else():
-                    m.d.sync += self.bus_o.eq(0)
+                    m.next = "WRITE"
+
+            with m.State("WRITE_WAIT_FOR_LAST"):
+                m.d.sync += self.bus_o.eq(0)
 
                 with m.If(self.bus_i.last):
                     m.d.sync += seq_num_expected.eq(seq_num_expected + 1)
@@ -171,9 +179,6 @@ class EthernetBridge(Elaboratable):
                     m.d.sync += self.last_o.eq(1)
                     m.next = "IDLE"  # TODO: could save a cycle by checking valid_i to see if there's more work to do
 
-                with m.Else():
-                    m.next = "WRITE"
-
             with m.State("NACK_WAIT_FOR_LAST"):
                 with m.If(self.last_i):
                     m.d.sync += self.data_o.eq(