test/test_refresh: add Refresher test

test/test_refresh.py

@@ -6,7 +6,7 @@ import unittest
 from migen import *
 
 from litedram.core.multiplexer import cmd_request_rw_layout
-from litedram.core.refresher import RefreshGenerator, RefreshTimer
+from litedram.core.refresher import RefreshGenerator, RefreshTimer, Refresher
 
 
 def c2bool(c):
@@ -33,8 +33,8 @@ class TestRefresh(unittest.TestCase):
     def test_refresh_generator(self):
         trp  = 1
         trfc = 2
-        class CMDS: pass
-        cmds = CMDS()
+        class Obj: pass
+        cmds = Obj()
         starts   = "_-______________"
         cmds.cas = "____-___________"
         cmds.ras = "___--___________"
@@ -65,3 +65,37 @@ class TestRefresh(unittest.TestCase):
     def test_refresh_timer(self):
         for i in range(1, 32):
             self.refresh_timer_test(i)
+
+    def test_refresher(self):
+        class Obj: pass
+        settings = Obj()
+        settings.with_refresh = True
+        settings.timing =Obj()
+        settings.timing.tREFI = 64
+        settings.timing.tRP   = 1
+        settings.timing.tRFC  = 2
+        settings.geom = Obj()
+        settings.geom.addressbits = 16
+        settings.geom.bankbits    = 3
+        settings.phy = Obj()
+        settings.phy.nranks = 1
+
+        def generator(dut):
+            dut.errors = 0
+            yield dut.cmd.ready.eq(1)
+            for i in range(16):
+                while (yield dut.cmd.valid) == 0:
+                    yield
+                cmd_valid_gap = 0
+                while (yield dut.cmd.valid) == 1:
+                    cmd_valid_gap += 1
+                    yield
+                while (yield dut.cmd.valid) == 0:
+                    cmd_valid_gap += 1
+                    yield
+                if cmd_valid_gap != (settings.timing.tREFI + 1):
+                    dut.errors += 1
+
+        dut = Refresher(settings)
+        run_simulation(dut, [generator(dut)])
+        self.assertEqual(dut.errors, 0)