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

import unittest
import random

from migen import *

from litedram.common import tXXDController

class TestTimingControllers(unittest.TestCase):
    def txxd_controller_test(self, txxd, loops):
        def generator(dut, valid_rand):
            prng = random.Random(42)
            for l in range(loops):
                while prng.randrange(100) < valid_rand:
                    yield
                yield dut.valid.eq(1)
                yield
                yield dut.valid.eq(0)

        @passive
        def checker(dut):
            dut.ready_gaps = []
            while True:
                while (yield dut.ready) != 0:
                    yield
                ready_gap = 1
                while (yield dut.ready) != 1:
                    ready_gap += 1
                    yield
                dut.ready_gaps.append(ready_gap)

        dut = tXXDController(txxd)
        run_simulation(dut, [generator(dut, valid_rand=90), checker(dut)])
        self.assertEqual(min(dut.ready_gaps), txxd)

    def test_txxd_controller(self):
        for i in range(2, 32):
            self.txxd_controller_test(i, 512)