test: add basic wishbone test

test/test_wishbone.py

@@ -0,0 +1,54 @@
+# This file is Copyright (c) 2018-2019 Florent Kermarrec <florent@enjoy-digital.fr>
+# License: BSD
+
+import unittest
+
+from migen import *
+from litex.gen.sim import run_simulation
+from litex.soc.interconnect import wishbone
+
+from litedram.frontend.wishbone import LiteDRAMWishbone2Native
+from litedram.common import LiteDRAMNativePort
+
+from test.common import DRAMMemory, seed_to_data
+
+
+class TestWishbone(unittest.TestCase):
+    def test_wishbone_data_width_not_smaller(self):
+        with self.assertRaises(AssertionError):
+            wb = wishbone.Interface(data_width=32)
+            port = LiteDRAMNativePort("both", address_width=32, data_width=wb.data_width * 2)
+            LiteDRAMWishbone2Native(wb, port)
+
+    def wishbone_readback_test(self, pattern, wishbone, port, mem_depth=64, **kwargs):
+        class DUT(Module):
+            def __init__(self):
+                self.port = port
+                self.wb = wishbone
+                self.submodules += LiteDRAMWishbone2Native(self.wb, self.port, **kwargs)
+                self.mem = DRAMMemory(port.data_width, mem_depth)
+
+        def main_generator(dut):
+            for adr, data in pattern:
+                yield from dut.wb.write(adr, data)
+                data_r = (yield from dut.wb.read(adr))
+                self.assertEqual(data_r, data)
+
+        dut = DUT()
+        generators = [
+            main_generator(dut),
+            dut.mem.write_handler(dut.port),
+            dut.mem.read_handler(dut.port),
+        ]
+        run_simulation(dut, generators)
+
+        mem_expected = [0] * mem_depth
+        for adr, data in pattern:
+            mem_expected[adr] = data
+        self.assertEqual(dut.mem.mem, mem_expected)
+
+    def test_wishbone(self):
+        pattern = [(adr, seed_to_data(adr, nbits=32)) for adr in range(16)]
+        wb = wishbone.Interface(data_width=32, adr_width=30)
+        port = LiteDRAMNativePort("both", address_width=30, data_width=32)
+        self.wishbone_readback_test(pattern, wb, port)