From b89ecdf91911b99087b756ba5fcd2a3adaa250fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C4=99drzej=20Boczar?= <jboczar@antmicro.com>
Date: Wed, 11 Mar 2020 15:18:44 +0100
Subject: [PATCH] test: add _LiteDRAMBISTGenerator tests

---
 test/test_bist.py | 88 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 85 insertions(+), 3 deletions(-)

diff --git a/test/test_bist.py b/test/test_bist.py
index e38e025..d74e5e1 100644
--- a/test/test_bist.py
+++ b/test/test_bist.py
@@ -29,9 +29,11 @@ class GenCheckDriver:
         yield self.module.reset.eq(0)
         yield
 
-    def run(self, base, length):
+    def run(self, base, length, end=None):
+        if end is None:
+            end = base + 0x100000
         yield self.module.base.eq(base)
-        yield self.module.end.eq(base + 0x100000)
+        yield self.module.end.eq(end)
         yield self.module.length.eq(length)
         yield self.module.run.eq(1)
         yield self.module.start.eq(1)
@@ -77,9 +79,89 @@ class TestBIST(unittest.TestCase):
 
          # simulation
         generators = [main_generator(dut)]
-        run_simulation(dut, main_generator(dut))
+        run_simulation(dut, generators)
         self.assertEqual(self.errors, 0)
 
+    def bist_generator_test(self, data_width, base, length, end, mem_depth, init_generator=None):
+        end_addr = base + length
+        start_word = base // (data_width//8)
+        end_word = end_addr // (data_width//8)
+        n_words = end_word - start_word
+
+        class DUT(Module):
+            def __init__(self):
+                self.write_port = LiteDRAMNativeWritePort(address_width=32, data_width=data_width)
+                self.submodules.generator = _LiteDRAMBISTGenerator(self.write_port)
+                self.mem = DRAMMemory(data_width, mem_depth)
+
+        def main_generator(dut):
+            generator = GenCheckDriver(dut.generator)
+
+            if init_generator is not None:
+                yield from init_generator(dut)
+
+            yield from generator.reset()
+            yield from generator.run(base, length, end=end)
+            yield
+
+        dut = DUT()
+
+        generators = [
+            main_generator(dut),
+            dut.mem.write_handler(dut.write_port),
+        ]
+        return dut, generators
+
+    def test_bist_generator(self):
+        dut, generators = self.bist_generator_test(mem_depth=128, data_width=32, end=128 * 4,
+                                                   base=16, length=64)
+        run_simulation(dut, generators)
+
+        before = 16 // 4
+        mem_expected = [0] * before + list(range(64//4)) + [0] * (128 - 64//4 - before)
+        self.assertEqual(dut.mem.mem, mem_expected)
+
+    def test_bist_generator_random_data(self):
+        def init(dut):
+            yield dut.generator.random_data.eq(1)
+            yield
+
+        # fill whole memory
+        dut, generators = self.bist_generator_test(mem_depth=128, data_width=32, end=128 * 4,
+                                                   base=0, length=128 * 4, init_generator=init)
+        run_simulation(dut, generators)
+
+        # only check if there are no duplicates and if data is not a simple sequence
+        self.assertEqual(len(set(dut.mem.mem)), len(dut.mem.mem), msg='Duplicate values in memory')
+        self.assertNotEqual(dut.mem.mem, list(range(128)), msg='Values are a sequence')
+
+    def test_bist_generator_random_addr(self):  # write whole memory and check if there are no repetitions?
+        def init(dut):
+            yield dut.generator.random_addr.eq(1)
+            yield
+
+        # fill whole memory
+        dut, generators = self.bist_generator_test(mem_depth=128, data_width=32, end=128 * 4,
+                                                   base=0, length=128 * 4, init_generator=init)
+        run_simulation(dut, generators)
+
+        # with random address and address wrapping (generator.end) we _can_ have duplicates
+        # we can at least check that the values written are not an ordered sequence
+        self.assertNotEqual(dut.mem.mem, list(range(128)), msg='Values are a sequence')
+
+    def test_bist_generator_wraps_addr(self):
+        dut, generators = self.bist_generator_test(mem_depth=128, data_width=32,
+                                                   base=16, length=96, end=32)
+        run_simulation(dut, generators)
+
+        # we restrict address to <16, 32) and write 96 bytes (which results in 96/4=24 words generated)
+        # this means that the address should wrap and last 8 generated words should overwrite memory
+        # at address <16, 24)
+        before = 16 // 4
+        mem_expected = [0] * 4 + list(range(16)) + [0] * (128 - 4 - 16)
+        mem_expected[4:4+8] = list(range(16, 24))
+        self.assertEqual(dut.mem.mem, mem_expected)
+
     def test_bist(self):
         class DUT(Module):
             def __init__(self):