drtio: add switching input test

artiq/gateware/test/drtio/test_switching.py

@@ -69,10 +69,11 @@ class Testbench:
         self.dut = DUT(2)
         self.now = 0
 
-    def init(self):
+    def init(self, with_buffer_space=True):
         yield from self.dut.master.rt_controller.csrs.underflow_margin.write(100)
         while not (yield from self.dut.master.link_layer.rx_up.read()):
             yield
+        if with_buffer_space:
             yield from self.get_buffer_space()
 
     def get_buffer_space(self):
@@ -106,13 +107,35 @@ class Testbench:
         if status & 0x4:
             return "destination unreachable"
 
+    def read(self, channel, timeout):
+        mcri = self.dut.master.cri
+        yield mcri.chan_sel.eq(channel)
+        yield mcri.timestamp.eq(timeout)
+        yield
+        yield mcri.cmd.eq(cri.commands["read"])
+        yield
+        yield mcri.cmd.eq(cri.commands["nop"])
+        yield
+        status = yield mcri.i_status
+        while status & 0x4:
+            yield
+            status = yield mcri.i_status
+        if status & 0x1:
+            return "timeout"
+        if status & 0x2:
+            return "overflow"
+        if status & 0x8:
+            return "destination unreachable"
+        return ((yield mcri.i_timestamp),
+                (yield mcri.i_data))
+
 
 class TestSwitching(unittest.TestCase):
     clocks = {"sys": 8, "rtio": 5, "rtio_rx": 5,
               "rio": 5, "rio_phy": 5,
               "sys_with_rst": 8, "rtio_with_rst": 5}
 
-    def test_switching(self):
+    def test_outputs(self):
         tb = Testbench()
 
         def test():
@@ -163,3 +186,64 @@ class TestSwitching(unittest.TestCase):
 
         run_simulation(tb.dut,
             {"sys": test(), "rtio": tb.dut.pr.receive(receive), "rtio_rx": send_replies()}, self.clocks)
+
+
+    def test_inputs(self):
+        tb = Testbench()
+
+        def test():
+            yield from tb.init(with_buffer_space=False)
+            reply = yield from tb.read(19, 145)
+            self.assertEqual(reply, (333, 23))
+            reply = yield from tb.read(20, 146)
+            self.assertEqual(reply, (334, 24))
+            reply = yield from tb.read(10, 34)
+            self.assertEqual(reply, "timeout")
+            reply = yield from tb.read(1, 20)
+            self.assertEqual(reply, "overflow")
+            reply = yield from tb.read(21, 147)
+            self.assertEqual(reply, (335, 25))
+            for _ in range(40):
+                yield
+
+        current_request = None
+
+        def get_request():
+            nonlocal current_request
+            while current_request is None:
+                yield
+            r = current_request
+            current_request = None
+            return r
+
+        def expect_read(chan_sel, timeout, reply):
+            packet_type, field_dict, trailer = yield from get_request()
+            self.assertEqual(packet_type, "read_request")
+            self.assertEqual(trailer, [])
+            self.assertEqual(field_dict["chan_sel"], chan_sel)
+            self.assertEqual(field_dict["timeout"], timeout)
+            if reply == "timeout":
+                yield from tb.dut.pt.send("read_reply_noevent", overflow=0)
+            elif reply == "overflow":
+                yield from tb.dut.pt.send("read_reply_noevent", overflow=1)
+            else:
+                timestamp, data = reply
+                yield from tb.dut.pt.send("read_reply", timestamp=timestamp, data=data)
+
+        @passive
+        def send_replies():
+            yield from expect_read(19, 145, (333, 23))
+            yield from expect_read(20, 146, (334, 24))
+            yield from expect_read(10, 34, "timeout")
+            yield from expect_read(1, 20, "overflow")
+            yield from expect_read(21, 147, (335, 25))
+            unexpected = yield from get_request()
+            self.fail("unexpected packet: {}".format(unexpected))
+
+        def receive(packet_type, field_dict, trailer):
+            nonlocal current_request
+            self.assertEqual(current_request, None)
+            current_request = (packet_type, field_dict, trailer)
+
+        run_simulation(tb.dut,
+            {"sys": test(), "rtio": tb.dut.pr.receive(receive), "rtio_rx": send_replies()}, self.clocks)