[PyCDE] Binding for FIFOs (#7806)

Adds a `seq` module which contains a FIFO class which produces a `seq.fifo` op. Does not include anything related to almost full/empty.

frontends/PyCDE/src/CMakeLists.txt

@@ -32,6 +32,7 @@ declare_mlir_python_sources(PyCDESources
   pycde/system.py
   pycde/devicedb.py
   pycde/instance.py
+  pycde/seq.py
   pycde/signals.py
   pycde/ndarray.py
   pycde/esi.py

frontends/PyCDE/src/pycde/seq.py

@@ -0,0 +1,61 @@
+#  Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+#  See https://llvm.org/LICENSE.txt for license information.
+#  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+from .circt.dialects import seq as raw_seq
+from .constructs import Wire
+
+from .types import Bits, Type
+from .signals import _FromCirctValue, BitsSignal, ClockSignal, Signal
+
+
+class FIFO:
+  """Creates a FIFO operation with the specified type, depth, clock, and reset
+  signal. Adds push and pop methods to wire up the FIFO."""
+
+  def __init__(self,
+               type: Type,
+               depth: int,
+               clk: ClockSignal,
+               rst: BitsSignal,
+               rd_latency: int = 0):
+    self.type = type
+    self.input = Wire(type)
+    self.wr_en = Wire(Bits(1))
+    self.rd_en = Wire(Bits(1))
+    i1 = Bits(1)._type
+    self.fifo = raw_seq.FIFOOp(self.input.type._type,
+                               i1,
+                               i1,
+                               i1,
+                               i1,
+                               self.input.value,
+                               self.rd_en.value,
+                               self.wr_en.value,
+                               clk.value,
+                               rst.value,
+                               depth,
+                               rdLatency=rd_latency)
+    self._output = _FromCirctValue(self.fifo.output)
+
+  def push(self, data: Signal, en: BitsSignal):
+    """Connect 'data' to the FIFO input and 'en' to write enable."""
+    self.input.assign(data)
+    self.wr_en.assign(en)
+
+  def pop(self, en: BitsSignal):
+    """Wire up 'en' to read enable and returns the FIFO output."""
+    self.rd_en.assign(en)
+    return self._output
+
+  @property
+  def output(self):
+    return self._output
+
+  @property
+  def full(self):
+    return _FromCirctValue(self.fifo.full)
+
+  @property
+  def empty(self):
+    return _FromCirctValue(self.fifo.empty)

frontends/PyCDE/test/test_seq.py

@@ -0,0 +1,53 @@
+# RUN: %PYTHON% %s | FileCheck %s
+
+from pycde import Module, Clock, Reset, Input, Output
+from pycde.seq import FIFO
+from pycde.testing import unittestmodule
+from pycde.types import Bits, UInt
+
+from pycde.module import generator
+
+# CHECK-LABEL: hw.module @SimpleFIFOTest(in %clk : !seq.clock, in %rst : i1)
+# CHECK-NEXT:      %false = hw.constant false
+# CHECK-NEXT:      [[R0:%.+]] = hwarith.constant 0 : ui32
+# CHECK-NEXT:      %out, %full, %empty, %almostFull, %almostEmpty = seq.fifo depth 16   in [[R0]] rdEn %false wrEn %false clk %clk rst %rst : ui32
+
+
+@unittestmodule(run_passes=False)
+class SimpleFIFOTest(Module):
+  clk = Clock()
+  rst = Reset()
+
+  @generator
+  def construct(ports):
+    c0 = Bits(1)(0)
+    ui32 = UInt(32)(0)
+
+    fifo = FIFO(type=UInt(32), depth=16, clk=ports.clk, rst=ports.rst)
+    fifo.push(ui32, c0)
+    fifo.pop(c0)
+
+
+# CHECK-LABEL: hw.module @SimpleFIFOTestRd1(in %clk : !seq.clock, in %rst : i1)
+# CHECK-NEXT:      %false = hw.constant false
+# CHECK-NEXT:      [[R0:%.+]] = hwarith.constant 0 : ui32
+# CHECK-NEXT:      %out, %full, %empty, %almostFull, %almostEmpty = seq.fifo depth 16 rd_latency 1  in [[R0]] rdEn %false wrEn %false clk %clk rst %rst : ui32
+
+
+@unittestmodule(run_passes=False)
+class SimpleFIFOTestRd1(Module):
+  clk = Clock()
+  rst = Reset()
+
+  @generator
+  def construct(ports):
+    c0 = Bits(1)(0)
+    ui32 = UInt(32)(0)
+
+    fifo = FIFO(type=UInt(32),
+                depth=16,
+                clk=ports.clk,
+                rst=ports.rst,
+                rd_latency=1)
+    fifo.push(ui32, c0)
+    fifo.pop(c0)