Merge pull request #178 from antmicro/jboc/unit-tests-crossbar

Add litedram.core.crossbar tests
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enjoy-digital 2020-04-10 19:41:45 +02:00 committed by GitHub
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3 changed files with 566 additions and 1 deletions

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@ -36,6 +36,58 @@ def timeout_generator(ticks):
raise TimeoutError("Timeout after %d ticks" % ticks)
class NativePortDriver:
"""Generates sequences for reading/writing to LiteDRAMNativePort
The write/read versions with wait_data=False are a cheap way to perform
burst during which the port is being held locked, but this way all the
data is being lost (would require separate coroutine to handle data).
"""
def __init__(self, port):
self.port = port
def read(self, address, wait_data=True):
yield self.port.cmd.valid.eq(1)
yield self.port.cmd.we.eq(0)
yield self.port.cmd.addr.eq(address)
yield
while (yield self.port.cmd.ready) == 0:
yield
yield self.port.cmd.valid.eq(0)
yield
if wait_data:
while (yield self.port.rdata.valid) == 0:
yield
data = (yield self.port.rdata.data)
yield self.port.rdata.ready.eq(1)
yield
yield self.port.rdata.ready.eq(0)
yield
return data
else:
yield self.port.rdata.ready.eq(1)
def write(self, address, data, we=None, wait_data=True):
if we is None:
we = 2**self.port.wdata.we.nbits - 1
yield self.port.cmd.valid.eq(1)
yield self.port.cmd.we.eq(1)
yield self.port.cmd.addr.eq(address)
yield
while (yield self.port.cmd.ready) == 0:
yield
yield self.port.cmd.valid.eq(0)
yield self.port.wdata.valid.eq(1)
yield self.port.wdata.data.eq(data)
yield self.port.wdata.we.eq(we)
yield
if wait_data:
while (yield self.port.wdata.ready) == 0:
yield
yield self.port.wdata.valid.eq(0)
yield
class CmdRequestRWDriver:
"""Simple driver for Endpoint(cmd_request_rw_layout())"""
def __init__(self, req, i=0, ep_layout=True, rw_layout=True):

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@ -256,7 +256,7 @@ class TestBankMachine(unittest.TestCase):
def test_burst_no_request_lost(self):
# Verify that no request is lost in fast bursts of requests regardless of cmd_buffer_depth
for cmd_buffer_depth in [8]:
for cmd_buffer_depth in [8, 1, 0]:
settings = dict(cmd_buffer_depth=cmd_buffer_depth)
with self.subTest(**settings):
dut = BankMachineDUT(1, controller_settings=settings)

513
test/test_crossbar.py Normal file
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@ -0,0 +1,513 @@
# This file is Copyright (c) 2020 Antmicro <www.antmicro.com>
# License: BSD
import random
import unittest
import functools
import itertools
from collections import namedtuple, defaultdict
from migen import *
from litedram.common import *
from litedram.core.crossbar import LiteDRAMCrossbar
from test.common import timeout_generator, NativePortDriver
class ControllerStub:
"""Simplified simulation of LiteDRAMController as seen by LiteDRAMCrossbar
This is a simplified implementation of LiteDRAMController suitable for
testing the crossbar. It consisits of bankmachine handlers that try to mimic
behaviour of real BankMachines. They also simulate data transmission by
scheduling it to appear on data interface (data_handler sets it).
"""
W = namedtuple("WriteData", ["bank", "addr", "data", "we"])
R = namedtuple("ReadData", ["bank", "addr", "data"])
WaitingData = namedtuple("WaitingData", ["delay", "data"])
def __init__(self, controller_interface, write_latency, read_latency, cmd_delay=None):
self.interface = controller_interface
self.write_latency = write_latency
self.read_latency = read_latency
self.data = [] # data registered on datapath (W/R)
self._waiting = [] # data waiting to be set on datapath
# incremental generator of artificial read data
self._read_data = itertools.count(0x10)
# simulated dealy of command processing, by default just constant
self._cmd_delay = cmd_delay or (lambda: 6)
# minimal logic required so that no two banks will become ready at the same moment
self._multiplexer_lock = None
def generators(self):
bank_handlers = [self.bankmachine_handler(bn) for bn in range(self.interface.nbanks)]
return [self.data_handler(), *bank_handlers]
@passive
def data_handler(self):
# Responsible for passing data over datapath with requested latency
while True:
# Examine requests to find if there is any for that cycle
available = [w for w in self._waiting if w.delay == 0]
# Make sure that it is never the case that we have more then 1
# operation of the same type
type_counts = defaultdict(int)
for a in available:
type_counts[type(a.data)] += 1
for t, count in type_counts.items():
assert count == 1, \
"%d data operations of type %s at the same time!" % (count, t.__name__)
for a in available:
# Remove it from the list and get the data
current = self._waiting.pop(self._waiting.index(a)).data
# If this was a write, then fill it with data from this cycle
if isinstance(current, self.W):
current = current._replace(
data=(yield self.interface.wdata),
we=(yield self.interface.wdata_we),
)
# If this was a read, then assert the data now
elif isinstance(current, self.R):
yield self.interface.rdata.eq(current.data)
else:
raise TypeError(current)
# Add it to the data that appeared on the datapath
self.data.append(current)
# Advance simulation time by 1 cycle
for i, w in enumerate(self._waiting):
self._waiting[i] = w._replace(delay=w.delay - 1)
yield
@passive
def bankmachine_handler(self, n):
# Simplified simulation of a bank machine.
# Uses a single buffer (no input fifo). Generates random read data.
bank = getattr(self.interface, "bank%d" % n)
while True:
# Wait for a valid bank command
while not (yield bank.valid):
# The lock is being held as long as there is a valid command
# in the buffer or there is a valid command on the interface.
# As at this point we have nothing in the buffer, we unlock
# the lock only if the command on the interface is not valid.
yield bank.lock.eq(0)
yield
# Latch the command to the internal buffer
cmd_addr = (yield bank.addr)
cmd_we = (yield bank.we)
# Lock the buffer as soon as command is valid on the interface.
# We do this 1 cycle after we see the command, but BankMachine
# also has latency, because cmd_buffer_lookahead.source must
# become valid.
yield bank.lock.eq(1)
yield bank.ready.eq(1)
yield
yield bank.ready.eq(0)
# Simulate that we are processing the command
for _ in range(self._cmd_delay()):
yield
# Avoid situation that can happen due to the lack of multiplexer,
# where more than one bank would send data at the same moment
while self._multiplexer_lock is not None:
yield
self._multiplexer_lock = n
yield
# After READ/WRITE has been issued, this is signalized by using
# rdata_valid/wdata_ready. The actual data will appear with latency.
if cmd_we: # WRITE
yield bank.wdata_ready.eq(1)
yield
yield bank.wdata_ready.eq(0)
# Send a request to the data_handler, it will check what
# has been sent from the crossbar port.
wdata = self.W(bank=n, addr=cmd_addr,
data=None, we=None) # to be filled in callback
self._waiting.append(self.WaitingData(data=wdata, delay=self.write_latency))
else: # READ
yield bank.rdata_valid.eq(1)
yield
yield bank.rdata_valid.eq(0)
# Send a request with "data from memory" to the data_handler
rdata = self.R(bank=n, addr=cmd_addr, data=next(self._read_data))
# Decrease latecy, as data_handler sets data with 1 cycle delay
self._waiting.append(self.WaitingData(data=rdata, delay=self.read_latency - 1))
# At this point cmd_buffer.source.ready has been activated and the
# command in internal buffer has been discarded. The lock will be
self._multiplexer_lock = None
# removed in next loop if there is no other command pending.
yield
class CrossbarDUT(Module):
default_controller_settings = dict(
cmd_buffer_depth=8,
address_mapping="ROW_BANK_COL",
)
default_phy_settings = dict(
cwl=2,
nphases=2,
nranks=1,
memtype="DDR2",
dfi_databits=2*16,
read_latency=5,
write_latency=1,
)
default_geom_settings = dict(
bankbits=3,
rowbits=13,
colbits=10,
)
def __init__(self, controller_settings=None, phy_settings=None, geom_settings=None):
# update settings if provided
def updated(settings, update):
copy = settings.copy()
copy.update(update or {})
return copy
controller_settings = updated(self.default_controller_settings, controller_settings)
phy_settings = updated(self.default_phy_settings, phy_settings)
geom_settings = updated(self.default_geom_settings, geom_settings)
class SimpleSettings(Settings):
def __init__(self, **kwargs):
self.set_attributes(kwargs)
settings = SimpleSettings(**controller_settings)
settings.phy = SimpleSettings(**phy_settings)
settings.geom = SimpleSettings(**geom_settings)
self.settings = settings
self.address_align = log2_int(burst_lengths[settings.phy.memtype])
self.interface = LiteDRAMInterface(self.address_align, settings)
self.submodules.crossbar = LiteDRAMCrossbar(self.interface)
def addr_port(self, bank, row, col):
# construct an address the way port master would do it
assert self.settings.address_mapping == "ROW_BANK_COL"
aa = self.address_align
cb = self.settings.geom.colbits
rb = self.settings.geom.rowbits
bb = self.settings.geom.bankbits
col = (col & (2**cb - 1)) >> aa
bank = (bank & (2**bb - 1)) << (cb - aa)
row = (row & (2**rb - 1)) << (cb + bb - aa)
return row | bank | col
def addr_iface(self, row, col):
# construct address the way bankmachine should receive it
aa = self.address_align
cb = self.settings.geom.colbits
rb = self.settings.geom.rowbits
col = (col & (2**cb - 1)) >> aa
row = (row & (2**rb - 1)) << (cb - aa)
return row | col
class TestCrossbar(unittest.TestCase):
W = ControllerStub.W
R = ControllerStub.R
def test_init(self):
dut = CrossbarDUT()
dut.crossbar.get_port()
dut.finalize()
def crossbar_test(self, dut, generators, timeout=100, **kwargs):
# Runs simulation with a controller stub (passive generators) and user generators
if not isinstance(generators, list):
generators = [generators]
controller = ControllerStub(dut.interface,
write_latency=dut.settings.phy.write_latency,
read_latency=dut.settings.phy.read_latency,
**kwargs)
generators += [*controller.generators(), timeout_generator(timeout)]
run_simulation(dut, generators)
return controller.data
def test_available_address_mappings(self):
# Check that the only supported address mapping is ROW_BANK_COL
# (if we start supporting new mappings, then update these tests to also
# test these other mappings)
def finalize_crossbar(mapping):
dut = CrossbarDUT(controller_settings=dict(address_mapping=mapping))
dut.crossbar.get_port()
dut.crossbar.finalize()
for mapping in ["ROW_BANK_COL", "BANK_ROW_COL"]:
if mapping in ["ROW_BANK_COL"]:
finalize_crossbar(mapping)
else:
with self.assertRaises(KeyError):
finalize_crossbar(mapping)
def test_address_mappings(self):
# Verify that address is translated correctly
reads = []
def producer(dut, port):
driver = NativePortDriver(port)
for t in transfers:
addr = dut.addr_port(bank=t["bank"], row=t["row"], col=t["col"])
if t["rw"] == self.W:
yield from driver.write(addr, data=t["data"], we=t.get("we", None))
elif t["rw"] == self.R:
data = (yield from driver.read(addr))
reads.append(data)
else:
raise TypeError(t["rw"])
geom_settings = dict(colbits=10, rowbits=13, bankbits=2)
dut = CrossbarDUT(geom_settings=geom_settings)
port = dut.crossbar.get_port()
transfers = [
dict(rw=self.W, bank=2, row=0x30, col=0x03, data=0x20),
dict(rw=self.W, bank=3, row=0x30, col=0x03, data=0x21),
dict(rw=self.W, bank=2, row=0xab, col=0x03, data=0x22),
dict(rw=self.W, bank=2, row=0x30, col=0x13, data=0x23),
dict(rw=self.R, bank=1, row=0x10, col=0x99),
dict(rw=self.R, bank=0, row=0x10, col=0x99),
dict(rw=self.R, bank=1, row=0xcd, col=0x99),
dict(rw=self.R, bank=1, row=0x10, col=0x77),
]
expected = []
for i, t in enumerate(transfers):
cls = t["rw"]
addr = dut.addr_iface(row=t["row"], col=t["col"])
if cls == self.W:
kwargs = dict(data=t["data"], we=0xff)
elif cls == self.R:
kwargs = dict(data=0x10 + i)
return cls(bank=t["bank"], addr=addr, **kwargs)
data = self.crossbar_test(dut, producer(port))
self.assertEqual(data, expected)
def test_arbitration(self):
# Create multiple masters that write to the same bank at the same time
# and verify that all the requests have been sent correctly.
def producer(dut, port, num):
driver = NativePortDriver(port)
addr = dut.addr_port(bank=3, row=0x10 + num, col=0x20 + num)
yield from driver.write(addr, data=0x30 + num)
dut = CrossbarDUT()
ports = [dut.crossbar.get_port() for _ in range(4)]
masters = [producer(dut, port, i) for i, port in enumerate(ports)]
data = self.crossbar_test(dut, masters)
expected = {
self.W(bank=3, addr=dut.addr_iface(row=0x10, col=0x20), data=0x30, we=0xff),
self.W(bank=3, addr=dut.addr_iface(row=0x11, col=0x21), data=0x31, we=0xff),
self.W(bank=3, addr=dut.addr_iface(row=0x12, col=0x22), data=0x32, we=0xff),
self.W(bank=3, addr=dut.addr_iface(row=0x13, col=0x23), data=0x33, we=0xff),
}
self.assertEqual(set(data), expected)
def test_lock_write(self):
# Verify that the locking mechanism works
# Create a situation when one master A wants to write to banks 0 then 1,
# but master B is continuously writing to bank 1 (bank is locked) so
# that master A is blocked. We use wait_data=False because we are only
# concerned about sending commands fast enough for the lock to be held
# continuously.
def master_a(dut, port):
driver = NativePortDriver(port)
adr = functools.partial(dut.addr_port, row=1, col=1)
write = functools.partial(driver.write, wait_data=False)
yield from write(adr(bank=0), data=0x10)
yield from write(adr(bank=1), data=0x11)
yield from write(adr(bank=0), data=0x12, wait_data=True)
def master_b(dut, port):
driver = NativePortDriver(port)
adr = functools.partial(dut.addr_port, row=2, col=2)
write = functools.partial(driver.write, wait_data=False)
yield from write(adr(bank=1), data=0x20)
yield from write(adr(bank=1), data=0x21)
yield from write(adr(bank=1), data=0x22)
yield from write(adr(bank=1), data=0x23)
yield from write(adr(bank=1), data=0x24)
dut = CrossbarDUT()
ports = [dut.crossbar.get_port() for _ in range(2)]
data = self.crossbar_test(dut, [master_a(dut, ports[0]), master_b(dut, ports[1])])
expected = [
self.W(bank=0, addr=dut.addr_iface(row=1, col=1), data=0x10, we=0xff), # A
self.W(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x20, we=0xff), # B
self.W(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x21, we=0xff), # B
self.W(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x22, we=0xff), # B
self.W(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x23, we=0xff), # B
self.W(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x24, we=0xff), # B
self.W(bank=1, addr=dut.addr_iface(row=1, col=1), data=0x11, we=0xff), # A
self.W(bank=0, addr=dut.addr_iface(row=1, col=1), data=0x12, we=0xff), # A
]
self.assertEqual(data, expected)
def test_lock_read(self):
# Verify that the locking mechanism works
def master_a(dut, port):
driver = NativePortDriver(port)
adr = functools.partial(dut.addr_port, row=1, col=1)
read = functools.partial(driver.read, wait_data=False)
yield from read(adr(bank=0))
yield from read(adr(bank=1))
yield from read(adr(bank=0))
# wait for read data to show up
for _ in range(16):
yield
def master_b(dut, port):
driver = NativePortDriver(port)
adr = functools.partial(dut.addr_port, row=2, col=2)
read = functools.partial(driver.read, wait_data=False)
yield from read(adr(bank=1))
yield from read(adr(bank=1))
yield from read(adr(bank=1))
yield from read(adr(bank=1))
yield from read(adr(bank=1))
dut = CrossbarDUT()
ports = [dut.crossbar.get_port() for _ in range(2)]
data = self.crossbar_test(dut, [master_a(dut, ports[0]), master_b(dut, ports[1])])
expected = [
self.R(bank=0, addr=dut.addr_iface(row=1, col=1), data=0x10), # A
self.R(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x11), # B
self.R(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x12), # B
self.R(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x13), # B
self.R(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x14), # B
self.R(bank=1, addr=dut.addr_iface(row=2, col=2), data=0x15), # B
self.R(bank=1, addr=dut.addr_iface(row=1, col=1), data=0x16), # A
self.R(bank=0, addr=dut.addr_iface(row=1, col=1), data=0x17), # A
]
self.assertEqual(data, expected)
def crossbar_stress_test(self, dut, ports, n_banks, n_ops, clocks=None):
# Runs simulation with multiple masters writing and reading to multiple banks
controller = ControllerStub(dut.interface,
write_latency=dut.settings.phy.write_latency,
read_latency=dut.settings.phy.read_latency)
# Store data produced per master
produced = defaultdict(list)
prng = random.Random(42)
def master(dut, port, num):
# Choose operation types based on port mode
ops_choice = {
"both": ["w", "r"],
"write": ["w"],
"read": ["r"],
}[port.mode]
driver = NativePortDriver(port)
for i in range(n_ops):
bank = prng.randrange(n_banks)
# We will later distinguish data by its row address
row = num
col = 0x20 * num + i
addr = dut.addr_port(bank=bank, row=row, col=col)
addr_iface = dut.addr_iface(row=row, col=col)
if prng.choice(ops_choice) == "w":
yield from driver.write(addr, data=i)
produced[num].append(self.W(bank, addr_iface, data=i, we=0xff))
else:
yield from driver.read(addr)
produced[num].append(self.R(bank, addr_iface, data=None))
for _ in range(8):
yield
generators = defaultdict(list)
for i, port in enumerate(ports):
generators[port.clock_domain].append(master(dut, port, i))
generators["sys"] += controller.generators()
generators["sys"].append(timeout_generator(80 * n_ops))
sim_kwargs = {}
if clocks is not None:
sim_kwargs["clocks"] = clocks
run_simulation(dut, generators, **sim_kwargs)
# split controller data by master, as this is what we want to compare
consumed = defaultdict(list)
for data in controller.data:
master = data.addr >> (dut.settings.geom.colbits - dut.address_align)
if isinstance(data, self.R):
# master couldn't know the data when it was sending
data = data._replace(data=None)
consumed[master].append(data)
return produced, consumed, controller.data
def test_stress(self):
# Test communication in complex scenarion
dut = CrossbarDUT()
ports = [dut.crossbar.get_port() for _ in range(8)]
produced, consumed, consumed_all = self.crossbar_stress_test(dut, ports, n_banks=4, n_ops=8)
for master in produced.keys():
self.assertEqual(consumed[master], produced[master], msg="master = %d" % master)
def test_stress_single_bank(self):
# Test communication in complex scenarion
dut = CrossbarDUT()
ports = [dut.crossbar.get_port() for _ in range(4)]
produced, consumed, consumed_all = self.crossbar_stress_test(dut, ports, n_banks=1, n_ops=8)
for master in produced.keys():
self.assertEqual(consumed[master], produced[master], msg="master = %d" % master)
def test_stress_single_master(self):
# Test communication in complex scenarion
dut = CrossbarDUT()
ports = [dut.crossbar.get_port() for _ in range(1)]
produced, consumed, consumed_all = self.crossbar_stress_test(dut, ports, n_banks=4, n_ops=8)
for master in produced.keys():
self.assertEqual(consumed[master], produced[master], msg="master = %d" % master)
def test_port_cdc(self):
# Verify that correct clock domain is being used
dut = CrossbarDUT()
port = dut.crossbar.get_port(clock_domain="other")
self.assertEqual(port.clock_domain, "other")
def test_stress_cdc(self):
# Verify communication when ports are in different clock domains
dut = CrossbarDUT()
clocks = {
"sys": 10,
"clk1": (7, 4),
"clk2": 12,
}
master_clocks = ["sys", "clk1", "clk2"]
ports = [dut.crossbar.get_port(clock_domain=clk) for clk in master_clocks]
produced, consumed, consumed_all = self.crossbar_stress_test(
dut, ports, n_banks=4, n_ops=6, clocks=clocks)
for master in produced.keys():
self.assertEqual(consumed[master], produced[master], msg="master = %d" % master)
def test_port_mode(self):
# Verify that ports in different modes can be requested
dut = CrossbarDUT()
for mode in ["both", "write", "read"]:
port = dut.crossbar.get_port(mode=mode)
self.assertEqual(port.mode, mode)
# NOTE: Stress testing with different data widths would require complicating
# the logic a lot to support registering data comming in multiple words (in
# data_handler), address shifting and recreation of packets. Because of this,
# and because data width converters are tested separately in test_adaptation,
# here we only test if ports report correct data widths.
def test_port_data_width_conversion(self):
# Verify that correct port data widths are being used
dut = CrossbarDUT()
dw = dut.interface.data_width
data_widths = [dw*2, dw, dw//2]
modes = ["both", "write", "read"]
for mode, data_width in itertools.product(modes, data_widths):
with self.subTest(mode=mode, data_width=data_width):
# up conversion is supported only for single direction ports
if mode == "both" and data_width < dut.interface.data_width:
with self.assertRaises(NotImplementedError):
dut.crossbar.get_port(mode=mode, data_width=data_width)
else:
port = dut.crossbar.get_port(mode=mode, data_width=data_width)
self.assertEqual(port.data_width, data_width)