From be91c7944239e07b86ee9e28d12969638a486334 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Thu, 1 Apr 2021 15:42:17 +0100
Subject: [PATCH] add cocotb testbench

---
 ls180/.gitignore         |   2 +
 ls180/cocotb/.gitignore  |   1 +
 ls180/cocotb/clean.sh    |   3 +
 ls180/cocotb/idcode.svf  |   4 ++
 ls180/cocotb/run_ghdl.sh |  11 ++++
 ls180/cocotb/test.py     | 117 +++++++++++++++++++++++++++++++++++++++
 6 files changed, 138 insertions(+)
 create mode 100644 ls180/cocotb/.gitignore
 create mode 100755 ls180/cocotb/clean.sh
 create mode 100644 ls180/cocotb/idcode.svf
 create mode 100755 ls180/cocotb/run_ghdl.sh
 create mode 100644 ls180/cocotb/test.py

diff --git a/ls180/.gitignore b/ls180/.gitignore
index 95373d1..88a919e 100644
--- a/ls180/.gitignore
+++ b/ls180/.gitignore
@@ -2,3 +2,5 @@ niolib/
 nsxlib/
 obj/
 vst_src/
+__pycache__/
+.*.sw?
diff --git a/ls180/cocotb/.gitignore b/ls180/cocotb/.gitignore
new file mode 100644
index 0000000..9b22a82
--- /dev/null
+++ b/ls180/cocotb/.gitignore
@@ -0,0 +1 @@
+test.ghw
diff --git a/ls180/cocotb/clean.sh b/ls180/cocotb/clean.sh
new file mode 100755
index 0000000..04882ff
--- /dev/null
+++ b/ls180/cocotb/clean.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+rm -fr results_*.xml sim_build_*
+
diff --git a/ls180/cocotb/idcode.svf b/ls180/cocotb/idcode.svf
new file mode 100644
index 0000000..994e9c8
--- /dev/null
+++ b/ls180/cocotb/idcode.svf
@@ -0,0 +1,4 @@
+!Loading device with 'idcode' instruction.
+SIR 4 TDI (1);
+SDR 32 TDI (00000000) TDO (000018FF) ;
+
diff --git a/ls180/cocotb/run_ghdl.sh b/ls180/cocotb/run_ghdl.sh
new file mode 100755
index 0000000..6c5e05b
--- /dev/null
+++ b/ls180/cocotb/run_ghdl.sh
@@ -0,0 +1,11 @@
+#!/bin/sh
+
+# Only run test in reset state as running CPU takes too much time to simulate
+make \
+  SIM=ghdl \
+  COCOTB_RESULTS_FILE=results_iverilog.xml \
+  COCOTB_HDL_TIMEUNIT=100ps \
+  TESTCASE="idcode_reset,idcodesvf_reset" \
+  SIM_BUILD=sim_build_iverilog
+
+
diff --git a/ls180/cocotb/test.py b/ls180/cocotb/test.py
new file mode 100644
index 0000000..9922bad
--- /dev/null
+++ b/ls180/cocotb/test.py
@@ -0,0 +1,117 @@
+import cocotb
+from cocotb.clock import Clock
+from cocotb.triggers import Timer
+from cocotb.utils import get_sim_steps
+from cocotb.binary import BinaryValue
+
+from c4m.cocotb.jtag.c4m_jtag import JTAG_Master
+from c4m.cocotb.jtag.c4m_jtag_svfcocotb import SVF_Executor
+
+#
+# Helper functions
+#
+
+def setup_sim(dut, *, clk_period, run):
+    """Initialize CPU and setup clock"""
+
+    clk_steps = get_sim_steps(clk_period, "ns")
+    cocotb.fork(Clock(dut.clk_from_pad, clk_steps).start())
+
+    dut.rst_from_pad <= 1
+    dut.clk_from_pad <= 0
+    if run:
+        yield Timer(int(10.5*clk_steps))
+        dut.rst_from_pad <= 0
+        yield Timer(int(5*clk_steps))
+
+def setup_jtag(dut, *, tck_period):
+    # Make this a generator
+    if False:
+        yield Timer(0)
+    return JTAG_Master(dut.jtag_tck, dut.jtag_tms,
+                       dut.jtag_tdi, dut.jtag_tdo,
+                       clk_period=tck_period)
+
+def execute_svf(dut, *, jtag, svf_filename):
+    jtag_svf = SVF_Executor(jtag)
+    with open(svf_filename, "r") as f:
+        svf_deck = f.read()
+    yield jtag_svf.run(svf_deck, p=dut._log.info)
+    
+#
+# IDCODE using JTAG_master
+#
+
+def idcode(dut, *, jtag):
+    jtag.IDCODE = [0, 0, 0, 1]
+    yield jtag.idcode()
+    result1 = jtag.result
+    dut._log.info("IDCODE1: {}".format(result1))
+    assert(result1 == BinaryValue("00000000000000000001100011111111"))
+
+    yield jtag.idcode()
+    result2 = jtag.result
+    dut._log.info("IDCODE2: {}".format(result2))
+
+    assert(result1 == result2)
+
+@cocotb.test()
+def idcode_reset(dut):
+    dut._log.info("Running IDCODE test; cpu in reset...")
+
+    clk_period = 100 # 10MHz
+    tck_period = 300 # 3MHz
+
+    yield from setup_sim(dut, clk_period=clk_period, run=False)
+    jtag = yield from setup_jtag(dut, tck_period = tck_period)
+
+    yield from idcode(dut, jtag=jtag)
+
+    dut._log.info("IDCODE test completed")
+
+@cocotb.test()
+def idcode_run(dut):
+    dut._log.info("Running IDCODE test; cpu running...")
+
+    clk_period = 100 # 10MHz
+    tck_period = 300 # 3MHz
+
+    yield from setup_sim(dut, clk_period=clk_period, run=True)
+    jtag = yield from setup_jtag(dut, tck_period = tck_period)
+
+    yield from idcode(dut, jtag=jtag)
+
+    dut._log.info("IDCODE test completed")
+
+#
+# Read IDCODE from SVF file
+#
+
+@cocotb.test()
+def idcodesvf_reset(dut):
+    dut._log.info("Running IDCODE through SVF test; cpu in reset...")
+
+    clk_period = 100 # 10MHz
+    tck_period = 300 # 3MHz
+
+    yield from setup_sim(dut, clk_period=clk_period, run=False)
+    jtag = yield from setup_jtag(dut, tck_period = tck_period)
+
+    yield from execute_svf(dut, jtag=jtag, svf_filename="idcode.svf")
+
+    dut._log.info("IDCODE test completed")
+
+@cocotb.test()
+def idcode_run(dut):
+    dut._log.info("Running IDCODE through test; cpu running...")
+
+    clk_period = 100 # 10MHz
+    tck_period = 300 # 3MHz
+
+    yield from setup_sim(dut, clk_period=clk_period, run=True)
+    jtag = yield from setup_jtag(dut, tck_period = tck_period)
+
+    yield from execute_svf(dut, jtag=jtag, svf_filename="idcode.svf")
+
+    dut._log.info("IDCODE test completed")
+
-- 
2.30.2