Files
cocotbext-axi/cocotbext/axi/stream.py
2021-03-06 17:30:05 -08:00

371 lines
11 KiB
Python

"""
Copyright (c) 2020 Alex Forencich
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""
import logging
from collections import deque
import cocotb
from cocotb.triggers import RisingEdge, Event, First, Timer
from cocotb.bus import Bus
from .reset import Reset
class StreamBus(Bus):
_signals = ["data"]
_optional_signals = []
def __init__(self, entity=None, prefix=None, **kwargs):
super().__init__(entity, prefix, self._signals, optional_signals=self._optional_signals, **kwargs)
@classmethod
def from_entity(cls, entity, **kwargs):
return cls(entity, **kwargs)
@classmethod
def from_prefix(cls, entity, prefix, **kwargs):
return cls(entity, prefix, **kwargs)
class StreamTransaction:
_signals = ["data"]
def __init__(self, *args, **kwargs):
for sig in self._signals:
if sig in kwargs:
setattr(self, sig, kwargs[sig])
del kwargs[sig]
else:
setattr(self, sig, 0)
super().__init__(*args, **kwargs)
def __repr__(self):
return f"{type(self).__name__}({', '.join(f'{s}={int(getattr(self, s))}' for s in self._signals)})"
class StreamBase(Reset):
_signals = ["data", "valid", "ready"]
_optional_signals = []
_signal_widths = {"valid": 1, "ready": 1}
_init_x = False
_valid_signal = "valid"
_valid_init = None
_ready_signal = "ready"
_ready_init = None
_transaction_obj = StreamTransaction
_bus_obj = StreamBus
def __init__(self, bus, clock, reset=None, reset_active_level=True, *args, **kwargs):
self.bus = bus
self.clock = clock
self.reset = reset
self.log = logging.getLogger(f"cocotb.{bus._entity._name}.{bus._name}")
super().__init__(*args, **kwargs)
self.active = False
self.queue = deque()
self.queue_sync = Event()
self.ready = None
self.valid = None
if self._ready_signal is not None and hasattr(self.bus, self._ready_signal):
self.ready = getattr(self.bus, self._ready_signal)
if self._ready_init is not None:
self.ready.setimmediatevalue(self._ready_init)
if self._valid_signal is not None and hasattr(self.bus, self._valid_signal):
self.valid = getattr(self.bus, self._valid_signal)
if self._valid_init is not None:
self.valid.setimmediatevalue(self._valid_init)
for sig in self._signals+self._optional_signals:
if hasattr(self.bus, sig):
if sig in self._signal_widths:
assert len(getattr(self.bus, sig)) == self._signal_widths[sig]
if self._init_x and sig not in (self._valid_signal, self._ready_signal):
v = getattr(self.bus, sig).value
v.binstr = 'x'*len(v)
getattr(self.bus, sig).setimmediatevalue(v)
self._run_cr = None
self._init_reset(reset, reset_active_level)
def count(self):
return len(self.queue)
def empty(self):
return not self.queue
def clear(self):
self.queue.clear()
def _handle_reset(self, state):
if state:
self.log.info("Reset asserted")
if self._run_cr is not None:
self._run_cr.kill()
self._run_cr = None
else:
self.log.info("Reset de-asserted")
if self._run_cr is None:
self._run_cr = cocotb.fork(self._run())
self.active = False
async def _run(self):
raise NotImplementedError()
class StreamPause:
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self.pause = False
self._pause_generator = None
self._pause_cr = None
def set_pause_generator(self, generator=None):
if self._pause_cr is not None:
self._pause_cr.kill()
self._pause_cr = None
self._pause_generator = generator
if self._pause_generator is not None:
self._pause_cr = cocotb.fork(self._run_pause())
def clear_pause_generator(self):
self.set_pause_generator(None)
async def _run_pause(self):
for val in self._pause_generator:
self.pause = val
await RisingEdge(self.clock)
class StreamSource(StreamBase, StreamPause):
_init_x = True
_valid_init = 0
_ready_init = None
async def send(self, obj):
self.send_nowait(obj)
def send_nowait(self, obj):
self.queue.append(obj)
def idle(self):
return self.empty() and not self.active
async def wait(self):
while not self.idle():
await RisingEdge(self.clock)
def _handle_reset(self, state):
super()._handle_reset(state)
if self.valid is not None:
self.valid <= 0
async def _run(self):
while True:
await RisingEdge(self.clock)
# read handshake signals
ready_sample = self.ready is None or self.ready.value
valid_sample = self.valid is None or self.valid.value
if (ready_sample and valid_sample) or (not valid_sample):
if self.queue and not self.pause:
self.bus.drive(self.queue.popleft())
if self.valid is not None:
self.valid <= 1
self.active = True
else:
if self.valid is not None:
self.valid <= 0
self.active = bool(self.queue)
class StreamMonitor(StreamBase):
_init_x = False
_valid_init = None
_ready_init = None
async def recv(self):
while self.empty():
self.queue_sync.clear()
await self.queue_sync.wait()
return self.recv_nowait()
def recv_nowait(self):
if self.queue:
return self.queue.popleft()
return None
async def wait(self, timeout=0, timeout_unit=None):
if not self.empty():
return
self.queue_sync.clear()
if timeout:
await First(self.queue_sync.wait(), Timer(timeout, timeout_unit))
else:
await self.queue_sync.wait()
async def _run(self):
while True:
await RisingEdge(self.clock)
# read handshake signals
ready_sample = self.ready is None or self.ready.value
valid_sample = self.valid is None or self.valid.value
if ready_sample and valid_sample:
obj = self._transaction_obj()
self.bus.sample(obj)
self.queue.append(obj)
self.queue_sync.set()
class StreamSink(StreamMonitor, StreamPause):
_init_x = False
_valid_init = None
_ready_init = 0
def __init__(self, bus, clock, reset=None, reset_active_level=True, *args, **kwargs):
super().__init__(bus, clock, reset, reset_active_level, *args, **kwargs)
self.queue_occupancy_limit = -1
def full(self):
if self.queue_occupancy_limit > 0 and len(self.queue) >= self.queue_occupancy_limit:
return True
else:
return False
def _handle_reset(self, state):
super()._handle_reset(state)
if self.ready is not None:
self.ready <= 0
async def _run(self):
while True:
await RisingEdge(self.clock)
# read handshake signals
ready_sample = self.ready is None or self.ready.value
valid_sample = self.valid is None or self.valid.value
if ready_sample and valid_sample:
obj = self._transaction_obj()
self.bus.sample(obj)
self.queue.append(obj)
self.queue_sync.set()
if self.ready is not None:
self.ready <= (not self.full() and not self.pause)
def define_stream(name, signals, optional_signals=None, valid_signal=None, ready_signal=None, signal_widths=None):
all_signals = signals.copy()
if optional_signals is None:
optional_signals = []
else:
all_signals += optional_signals
if valid_signal is None:
for s in all_signals:
if s.lower().endswith('valid'):
valid_signal = s
if valid_signal not in all_signals:
signals += valid_signal
if ready_signal is None:
for s in all_signals:
if s.lower().endswith('ready'):
ready_signal = s
else:
if ready_signal not in all_signals:
signals += ready_signal
if signal_widths is None:
signal_widths = {}
if valid_signal not in signal_widths:
signal_widths[valid_signal] = 1
if ready_signal not in signal_widths:
signal_widths[ready_signal] = 1
filtered_signals = []
for s in all_signals:
if s not in (ready_signal, valid_signal):
filtered_signals.append(s)
attrib = {}
attrib['_signals'] = signals
attrib['_optional_signals'] = optional_signals
bus = type(name+"Bus", (StreamBus,), attrib)
attrib = {s: 0 for s in filtered_signals}
attrib['_signals'] = filtered_signals
transaction = type(name+"Transaction", (StreamTransaction,), attrib)
attrib = {}
attrib['_signals'] = signals
attrib['_optional_signals'] = optional_signals
attrib['_signal_widths'] = signal_widths
attrib['_ready_signal'] = ready_signal
attrib['_valid_signal'] = valid_signal
attrib['_transaction_obj'] = transaction
attrib['_bus_obj'] = bus
source = type(name+"Source", (StreamSource,), attrib)
sink = type(name+"Sink", (StreamSink,), attrib)
monitor = type(name+"Monitor", (StreamMonitor,), attrib)
return bus, transaction, source, sink, monitor