# This file is Copyright (c) 2020 Antmicro # License: BSD import unittest from migen import * from litex.gen.sim import run_simulation from litex.soc.interconnect import stream from litedram.common import * from litedram.core.multiplexer import _CommandChooser, _Steerer, Multiplexer class CmdRequestRWDriver: def __init__(self, req): self.req = req self.bank = 0 self.row = 0 self.col = 0 def _drive(self, **kwargs): signals = [ "valid", "first", "last", "a", "ba", "cas", "ras", "we", "is_cmd", "is_read", "is_write" ] for s in signals: yield getattr(self.req, s).eq(kwargs.get(s, 0)) def activate(self): yield from self._drive(valid=1, is_cmd=1, ras=1, a=self.row, ba=self.bank) def precharge(self, all_banks=False): a = 0 if not all_banks else (1 << 10) yield from self._drive(valid=1, is_cmd=1, ras=1, we=1, a=a, ba=self.bank) def write(self, auto_precharge=False): assert not (self.col & (1 << 10)) col = self.col | (1 << 10) if auto_precharge else self.col yield from self._drive(valid=1, is_write=1, cas=1, we=1, a=col, ba=self.bank) def read(self, auto_precharge=False): assert not (self.col & (1 << 10)) col = self.col | (1 << 10) if auto_precharge else self.col yield from self._drive(valid=1, is_read=1, cas=1, a=col, ba=self.bank) def nop(self): yield from self._drive() class CommandChooserDUT(Module): def __init__(self, n_requests, addressbits, bankbits): self.requests = [stream.Endpoint(cmd_request_rw_layout(a=addressbits, ba=bankbits)) for _ in range(n_requests)] self.submodules.chooser = _CommandChooser(self.requests) self.drivers = [CmdRequestRWDriver(req) for req in self.requests] # set known a/ba to easly distinguish currently connected request for i, driver in enumerate(self.drivers): driver.bank = i driver.row = i driver.col = i def set_requests(self, description): assert len(description) == len(self.drivers) for driver, c in zip(self.drivers, description): method = { "w": driver.write, "r": driver.read, "a": driver.activate, "p": driver.precharge, "_": driver.nop, }[c] yield from method() class TestCommandChooser(unittest.TestCase): def test_helper_methods_correct(self): # Verify that helper methods return correct values def main_generator(dut): possible_cmds = "_rwap" expected_read = "01000" expected_write = "00100" expected_activate = "00010" helper_methods = { "write": expected_write, "read": expected_read, "activate": expected_activate, } # create a subTest for each method for method, expected_values in helper_methods.items(): with self.subTest(method=method): # Set each available command as the first request and verify # that the helper method returns the correct value. We can # safely use only the first request because no requests are # valid as all the want_* signals are 0. for cmd, expected in zip(possible_cmds, expected_values): yield from dut.set_requests(f"{cmd}___") yield method_value = (yield getattr(dut.chooser, method)()) self.assertEqual(method_value, int(expected)) # test accept helper with self.subTest(method="accept"): yield dut.chooser.want_writes.eq(1) yield yield from dut.set_requests("____") yield self.assertEqual((yield dut.chooser.accept()), 0) # set write request, this sets request.valid=1 yield from dut.set_requests("w___") yield self.assertEqual((yield dut.chooser.accept()), 0) self.assertEqual((yield dut.chooser.cmd.valid), 1) # accept() is only on after we set cmd.ready=1 yield dut.chooser.cmd.ready.eq(1) yield self.assertEqual((yield dut.chooser.accept()), 1) dut = CommandChooserDUT(n_requests=4, bankbits=3, addressbits=13) run_simulation(dut, main_generator(dut)) def test_selects_next_when_request_not_valid(self): def main_generator(dut): yield dut.chooser.want_cmds.eq(1) yield from dut.set_requests("pppp") yield # advance to next request def invalidate(i): yield dut.requests[i].valid.eq(0) yield yield dut.requests[i].valid.eq(1) yield # first request is selected as it is valid and ~ready self.assertEqual((yield dut.chooser.cmd.ba), 0) yield self.assertEqual((yield dut.chooser.cmd.ba), 0) # after deactivating valid arbiter should choose next request yield from invalidate(0) self.assertEqual((yield dut.chooser.cmd.ba), 1) yield from invalidate(1) self.assertEqual((yield dut.chooser.cmd.ba), 2) yield from invalidate(2) self.assertEqual((yield dut.chooser.cmd.ba), 3) yield from invalidate(3) self.assertEqual((yield dut.chooser.cmd.ba), 0) dut = CommandChooserDUT(n_requests=4, bankbits=3, addressbits=13) run_simulation(dut, main_generator(dut)) def test_selects_next_when_cmd_ready(self): def main_generator(dut): yield dut.chooser.want_cmds.eq(1) yield from dut.set_requests("pppp") yield # advance to next request def cmd_ready(): yield dut.chooser.cmd.ready.eq(1) yield yield dut.chooser.cmd.ready.eq(0) yield # first request is selected as it is valid and ~ready self.assertEqual((yield dut.chooser.cmd.ba), 0) yield self.assertEqual((yield dut.chooser.cmd.ba), 0) # after deactivating valid arbiter should choose next request yield from cmd_ready() self.assertEqual((yield dut.chooser.cmd.ba), 1) yield from cmd_ready() self.assertEqual((yield dut.chooser.cmd.ba), 2) yield from cmd_ready() self.assertEqual((yield dut.chooser.cmd.ba), 3) yield from cmd_ready() self.assertEqual((yield dut.chooser.cmd.ba), 0) dut = CommandChooserDUT(n_requests=4, bankbits=3, addressbits=13) run_simulation(dut, main_generator(dut)) def selection_test(self, requests, expected_order, wants): # Set requests to given states and tests whether they are being connected # to chooser.cmd in the expected order. Using `ba` value to distinguish # requests (as initialised in CommandChooserDUT). # "_" means no valid request. def main_generator(dut): for want in wants: yield getattr(dut.chooser, want).eq(1) yield from dut.set_requests(requests) yield for i, expected_index in enumerate(expected_order): error_msg = f"requests={requests}, expected_order={expected_order}, i={i}" if expected_index == "_": # not valid - cas/ras/we should be 0 cas = (yield dut.chooser.cmd.cas) ras = (yield dut.chooser.cmd.ras) we = (yield dut.chooser.cmd.we) self.assertEqual((cas, ras, we), (0, 0, 0), msg=error_msg) else: # check that ba is as expected selected_request_index = (yield dut.chooser.cmd.ba) self.assertEqual(selected_request_index, int(expected_index), msg=error_msg) # advance to next request yield dut.chooser.cmd.ready.eq(1) yield yield dut.chooser.cmd.ready.eq(0) yield assert len(requests) == 8 dut = CommandChooserDUT(n_requests=8, bankbits=3, addressbits=13) run_simulation(dut, main_generator(dut)) def test_selects_nothing(self): # When want_* = 0, chooser should set cas/ras/we = 0, which means not valid request requests = "w_rawpwr" order = "____" # cas/ras/we are never set self.selection_test(requests, order, wants=[]) def test_selects_writes(self): requests = "w_rawpwr" order = "0460460" self.selection_test(requests, order, wants=["want_writes"]) def test_selects_reads(self): requests = "rp_awrrw" order = "0560560" self.selection_test(requests, order, wants=["want_reads"]) def test_selects_writes_and_reads(self): requests = "rp_awrrw" order = "04567045670" self.selection_test(requests, order, wants=["want_reads", "want_writes"]) def test_selects_cmds_without_act(self): # When want_cmds = 1, but want_activates = 0, activate commands should not be selected requests = "pr_aa_pw" order = "06060" self.selection_test(requests, order, wants=["want_cmds"]) def test_selects_cmds_with_act(self): # When want_cmds/activates = 1, both activate and precharge should be selected requests = "pr_aa_pw" order = "034603460" self.selection_test(requests, order, wants=["want_cmds", "want_activates"]) def test_selects_nothing_when_want_activates_only(self): # When only want_activates = 1, nothing will be selected requests = "pr_aa_pw" order = "____" self.selection_test(requests, order, wants=["want_activates"]) def test_selects_cmds_and_writes(self): requests = "pr_aa_pw" order = "0670670" self.selection_test(requests, order, wants=["want_cmds", "want_writes"])