litex/misoclib/mem/sdram/test/refresher.py

from random import Random

from migen.fhdl.std import *
from migen.sim.generic import run_simulation

from misoclib.mem.sdram.core.lasmicon.refresher import *

from common import CommandLogger


class Granter(Module):
    def __init__(self, req, ack):
        self.req = req
        self.ack = ack
        self.state = 0
        self.prng = Random(92837)

    def do_simulation(self, selfp):
        elts = ["@" + str(selfp.simulator.cycle_counter)]

        if self.state == 0:
            if selfp.req:
                elts.append("Refresher requested access")
                self.state = 1
        elif self.state == 1:
            if self.prng.randrange(0, 5) == 0:
                elts.append("Granted access to refresher")
                selfp.ack = 1
                self.state = 2
        elif self.state == 2:
            if not selfp.req:
                elts.append("Refresher released access")
                selfp.ack = 0
                self.state = 0

        if len(elts) > 1:
            print("\t".join(elts))


class TB(Module):
    def __init__(self):
        self.submodules.dut = Refresher(13, 2, tRP=3, tREFI=100, tRFC=5)
        self.submodules.logger = CommandLogger(self.dut.cmd)
        self.submodules.granter = Granter(self.dut.req, self.dut.ack)

if __name__ == "__main__":
    run_simulation(TB(), ncycles=400)