bench: reduce buffer_depth/burst_size to 128 (maximum supported by Etherbone protocol is 255).

bench/arty.py

@@ -42,7 +42,7 @@ class BenchSoC(SoCCore):
             pads       = self.platform.request("eth"),
             with_hw_init_reset = False)
         self.add_csr("ethphy")
-        self.add_etherbone(phy=self.ethphy, buffer_depth=256)
+        self.add_etherbone(phy=self.ethphy, buffer_depth=128)
 
         # SRAM -------------------------------------------------------------------------------------
         self.add_ram("sram", 0x20000000, 0x1000)

bench/colorlight_5a_75b.py

@@ -43,7 +43,7 @@ class BenchSoC(SoCCore):
             tx_delay   = 0e-9,
             with_hw_init_reset = False)
         self.add_csr("ethphy")
-        self.add_etherbone(phy=self.ethphy, buffer_depth=256)
+        self.add_etherbone(phy=self.ethphy, buffer_depth=128)
 
         # SRAM -------------------------------------------------------------------------------------
         self.add_ram("sram", 0x20000000, 0x1000)

bench/genesys2.py

@@ -42,7 +42,7 @@ class BenchSoC(SoCCore):
             pads       = self.platform.request("eth"),
             with_hw_init_reset = False)
         self.add_csr("ethphy")
-        self.add_etherbone(phy=self.ethphy, buffer_depth=256)
+        self.add_etherbone(phy=self.ethphy, buffer_depth=128)
 
         # SRAM -------------------------------------------------------------------------------------
         self.add_ram("sram", 0x20000000, 0x1000)

bench/test_etherbone.py

@@ -105,7 +105,7 @@ def speed_test(port):
     wb.open()
 
     test_size  = 16*KiB
-    burst_size = 255 # FIXME: Use 256, fix Etherbone encoding.
+    burst_size = 128
 
     print("Testing write speed... ", end="")
     start = time.time()