110 lines
3.1 KiB
Python
110 lines
3.1 KiB
Python
#
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# This file is part of LiteX.
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#
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# Copyright (c) 2019 Florent Kermarrec <florent@enjoy-digital.fr>
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# SPDX-License-Identifier: BSD-2-Clause
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import unittest
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from migen import *
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from litex.soc.cores.prbs import *
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class PRBSModel:
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def __init__(self, n_state=23, taps=[17, 22]):
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self.n_state = n_state
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self.taps = taps
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self.state = 1
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def getbit(self):
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feedback = 0
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for tap in self.taps:
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feedback = feedback ^ (self.state >> tap) & 0x1
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self.state = (self.state << 1) & (2**self.n_state-1) | feedback
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return feedback
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def getbits(self, n):
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v = 0
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for i in range(n):
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v <<= 1
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v |= self.getbit()
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return v
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class PRBS7Model(PRBSModel):
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def __init__(self):
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PRBSModel.__init__(self, n_state=7, taps=[5, 6])
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class PRBS15Model(PRBSModel):
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def __init__(self):
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PRBSModel.__init__(self, n_state=15, taps=[13, 14])
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class PRBS31Model(PRBSModel):
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def __init__(self):
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PRBSModel.__init__(self, n_state=31, taps=[27, 30])
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class TestPRBS(unittest.TestCase):
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def test_prbs_generator(self):
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duts = {
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"prbs7": PRBS7Generator(8),
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"prbs15": PRBS15Generator(16),
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"prbs31": PRBS31Generator(32),
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}
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models = {
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"prbs7": PRBS7Model(),
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"prbs15": PRBS15Model(),
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"prbs31": PRBS31Model(),
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}
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errors = 0
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for test in ["prbs7", "prbs15", "prbs31"]:
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dut = duts[test]
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dut._errors = 0
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model = models[test]
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def checker(dut, cycles):
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yield
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# Let the generator run and check values against model.
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for i in range(cycles):
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if (yield dut.o) != model.getbits(len(dut.o)):
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dut._errors += 1
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yield
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run_simulation(dut, checker(dut, 1024))
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self.assertEqual(dut._errors, 0)
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def test_prbs_checker(self):
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duts = {
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"prbs7": PRBS7Checker(8),
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"prbs15": PRBS15Checker(16),
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"prbs31": PRBS31Checker(32),
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}
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models = {
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"prbs7": PRBS7Model(),
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"prbs15": PRBS15Model(),
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"prbs31": PRBS31Model(),
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}
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errors = 0
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for test in ["prbs7", "prbs15", "prbs31"]:
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dut = duts[test]
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dut._errors = 0
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model = models[test]
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@passive
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def generator(dut):
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# Inject PRBS values from model.
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while True:
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yield dut.i.eq(model.getbits(len(dut.i)))
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yield
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def checker(dut, cycles):
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# Wait PRBS synchronization.
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for i in range(8):
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yield
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# Check that no errors are reported.
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for i in range(cycles):
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if (yield dut.errors) != 0:
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dut._errors += 1
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yield
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run_simulation(dut, [generator(dut), checker(dut, 1024)])
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self.assertEqual(dut._errors, 0)
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