litex/lib/sata/test/scrambler_tb.py

import subprocess

from migen.fhdl.std import *

from lib.sata.std import *
from lib.sata.link.scrambler import *

from lib.sata.test.common import *

class TB(Module):
	def __init__(self, length):
		self.submodules.scrambler = Scrambler()
		self.length = length

	def get_c_values(self, length):
		stdin = "0x%08x" %length
		with subprocess.Popen("./scrambler", stdin=subprocess.PIPE, stdout=subprocess.PIPE) as process:
			process.stdin.write(stdin.encode("ASCII"))
			out, err = process.communicate()
		return [int(e, 16) for e in out.decode("ASCII").split("\n")[:-1]]

	def gen_simulation(self, selfp):
		# init CRC
		selfp.scrambler.ce = 1
		selfp.scrambler.reset = 1
		yield
		selfp.scrambler.reset = 0

		# log results
		yield
		sim_values = []
		for i in range(self.length):
			sim_values.append(selfp.scrambler.value)
			yield

		# stop
		selfp.scrambler.ce = 0
		for i in range(32):
			yield

		# get C code reference
		c_values = self.get_c_values(self.length)

		# check results
		s, l, e = check(c_values, sim_values)
		print("shift "+ str(s) + " / length " + str(l) + " / errors " + str(e))

if __name__ == "__main__":
	from migen.sim.generic import run_simulation
	length = 8192
	run_simulation(TB(length), ncycles=length+100, vcd_name="my.vcd")