litedram/test/test_refresh.py

# This file is Copyright (c) 2019 Florent Kermarrec <florent@enjoy-digital.fr>
# License: BSD

import unittest

from migen import *

from litedram.core.multiplexer import cmd_request_rw_layout
from litedram.core.refresher import RefreshGenerator, RefreshTimer


def c2bool(c):
    return {"-": 1, "_": 0}[c]

class TestRefresh(unittest.TestCase):
    def refresh_generator_test(self, trp, trfc, starts, dones, cmds):
        cmd = Record(cmd_request_rw_layout(a=16, ba=3))
        def generator(dut):
            dut.errors = 0
            for start, done, cas, ras in zip(starts, dones, cmds.cas, cmds.ras):
                yield dut.start.eq(c2bool(start))
                yield
                if (yield dut.done) != c2bool(done):
                    dut.errors += 1
                if (yield cmd.cas) != c2bool(cas):
                    dut.errors += 1
                if (yield cmd.ras) != c2bool(ras):
                    dut.errors += 1
        dut = RefreshGenerator(cmd, trp, trfc)
        run_simulation(dut, [generator(dut)])
        self.assertEqual(dut.errors, 0)

    def test_refresh_generator(self):
        trp  = 1
        trfc = 2
        class CMDS: pass
        cmds = CMDS()
        starts   = "_-______________"
        cmds.cas = "____-___________"
        cmds.ras = "___--___________"
        dones    = "______-_________"
        self.refresh_generator_test(trp, trfc, starts, dones, cmds)

    def refresh_timer_test(self, trefi):
        def generator(dut):
            dut.errors = 0
            for i in range(16*(trefi + 1)):
                yield
                if i%(trefi + 1) == (trefi - 1):
                    if (yield dut.refresh.done) != 1:
                        dut.errors += 1
                else:
                    if (yield dut.refresh.done) != 0:
                        dut.errors += 1

        class DUT(Module):
            def __init__(self, trefi):
                self.submodules.refresh = RefreshTimer(trefi)
                self.comb += self.refresh.wait.eq(~self.refresh.done)

        dut = DUT(trefi)
        run_simulation(dut, [generator(dut)])
        self.assertEqual(dut.errors, 0)

    def test_refresh_timer(self):
        for i in range(1, 32):
            self.refresh_timer_test(i)