From a2f218479f33282ef472863fa05d112c9ad397d5 Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sat, 26 Sep 2020 15:42:24 +0100
Subject: [PATCH] create client-server version of jtag debug unit test

---
 src/soc/debug/test/test_jtag_tap_srv.py | 229 ++++++++++++++++++++++++
 1 file changed, 229 insertions(+)
 create mode 100644 src/soc/debug/test/test_jtag_tap_srv.py

diff --git a/src/soc/debug/test/test_jtag_tap_srv.py b/src/soc/debug/test/test_jtag_tap_srv.py
new file mode 100644
index 00000000..ae74f5ee
--- /dev/null
+++ b/src/soc/debug/test/test_jtag_tap_srv.py
@@ -0,0 +1,229 @@
+"""DMI 2 JTAG test
+
+based on Staf Verhaegen (Chips4Makers) wishbone TAP
+"""
+
+from nmigen import (Module, Signal, Elaboratable, Const)
+from c4m.nmigen.jtag.tap import TAP, IOType
+from c4m.nmigen.jtag.bus import Interface as JTAGInterface
+from soc.debug.dmi import DMIInterface, DBGCore
+from soc.debug.test.dmi_sim import dmi_sim
+from soc.debug.dmi2jtag import DMITAP
+from soc.debug.test.jtagremote import JTAGServer, JTAGClient
+
+from nmigen_soc.wishbone.sram import SRAM
+from nmigen import Memory, Signal, Module
+
+from nmigen.back.pysim import Simulator, Delay, Settle, Tick
+from nmutil.util import wrap
+
+def client_sync(dut):
+    tck = yield dut.cbus.tck
+    tms = yield dut.cbus.tms
+    tdi = yield dut.cbus.tdi
+    dut.c.jtagremote_client_send((tck, tms, tdi))
+    #print ("about to client recv")
+    while True:
+        tdo = dut.c.jtagremote_client_recv(timeout=0)
+        if tdo is not None:
+            break
+        yield
+    yield dut.cbus.tdo.eq(tdo)
+
+
+def tms_state_set(dut, bits):
+    for bit in bits:
+        yield dut.cbus.tck.eq(1)
+        yield dut.cbus.tms.eq(bit)
+        yield from client_sync(dut)
+        yield
+        yield dut.cbus.tck.eq(0)
+        yield from client_sync(dut)
+        yield
+        yield from client_sync(dut)
+    yield dut.cbus.tms.eq(0)
+    yield from client_sync(dut)
+
+
+def tms_data_getset(dut, tms, d_len, d_in=0):
+    res = 0
+    yield dut.cbus.tms.eq(tms)
+    for i in range(d_len):
+        tdi = 1 if (d_in & (1<<i)) else 0
+        yield dut.cbus.tck.eq(1)
+        yield from client_sync(dut)
+        res |= (1<<i) if (yield dut.bus.tdo) else 0
+        yield
+        yield from client_sync(dut)
+        yield dut.cbus.tdi.eq(tdi)
+        yield dut.cbus.tck.eq(0)
+        yield from client_sync(dut)
+        yield
+        yield from client_sync(dut)
+    yield dut.cbus.tms.eq(0)
+    yield from client_sync(dut)
+
+    return res
+
+
+def jtag_set_reset(dut):
+    yield from tms_state_set(dut, [1, 1, 1, 1, 1])
+
+def jtag_set_shift_dr(dut):
+    yield from tms_state_set(dut, [1, 0, 0])
+
+def jtag_set_shift_ir(dut):
+    yield from tms_state_set(dut, [1, 1, 0])
+
+def jtag_set_run(dut):
+    yield from tms_state_set(dut, [0])
+
+def jtag_set_idle(dut):
+    yield from tms_state_set(dut, [1, 1, 0])
+
+
+def jtag_read_write_reg(dut, addr, d_len, d_in=0):
+    yield from jtag_set_run(dut)
+    yield from jtag_set_shift_ir(dut)
+    yield from tms_data_getset(dut, 0, dut._ir_width, addr)
+    yield from jtag_set_idle(dut)
+
+    yield from jtag_set_shift_dr(dut)
+    result = yield from tms_data_getset(dut, 0, d_len, d_in)
+    yield from jtag_set_idle(dut)
+    return result
+
+
+# JTAG-ircodes for accessing DMI
+DMI_ADDR = 5
+DMI_READ = 6
+DMI_WRRD = 7
+
+# JTAG-ircodes for accessing Wishbone
+WB_ADDR = 8
+WB_READ = 9
+WB_WRRD = 10
+
+
+def jtag_srv(dut):
+    while not dut.stop:
+        # loop and receive data from client
+        tdo = yield dut.bus.tdo
+        #print ("server tdo data", tdo)
+        data = dut.s.jtagremote_server_recv(tdo)
+        #print ("server recv data", data)
+        if not data:
+            yield
+            continue
+        tck, tms, tdi = data
+        yield dut.bus.tck.eq(tck)
+        yield dut.bus.tms.eq(tms)
+        yield dut.bus.tdi.eq(tdi)
+        yield
+
+
+def jtag_sim(dut):
+
+    ####### JTAGy stuff (IDCODE) ######
+
+    # read idcode
+    yield from jtag_set_reset(dut)
+    idcode = yield from jtag_read_write_reg(dut, 0b1, 32)
+    print ("idcode", hex(idcode))
+    assert idcode == 0x18ff
+
+    ####### JTAG to DMI ######
+
+    # write DMI address
+    yield from jtag_read_write_reg(dut, DMI_ADDR, 8, DBGCore.CTRL)
+
+    # read DMI CTRL register
+    status = yield from jtag_read_write_reg(dut, DMI_READ, 64)
+    print ("dmi ctrl status", hex(status))
+    assert status == 4
+
+    # write DMI address
+    yield from jtag_read_write_reg(dut, DMI_ADDR, 8, 0)
+
+    # write DMI CTRL register
+    status = yield from jtag_read_write_reg(dut, DMI_WRRD, 64, 0b101)
+    print ("dmi ctrl status", hex(status))
+    assert status == 4 # returned old value (nice! cool feature!)
+
+    # write DMI address
+    yield from jtag_read_write_reg(dut, DMI_ADDR, 8, DBGCore.CTRL)
+
+    # read DMI CTRL register
+    status = yield from jtag_read_write_reg(dut, DMI_READ, 64)
+    print ("dmi ctrl status", hex(status))
+    assert status == 5
+
+    # write DMI MSR address
+    yield from jtag_read_write_reg(dut, DMI_ADDR, 8, DBGCore.MSR)
+
+    # read DMI MSR register
+    msr = yield from jtag_read_write_reg(dut, DMI_READ, 64)
+    print ("dmi msr", hex(msr))
+    assert msr == 0xdeadbeef
+
+    ####### JTAG to Wishbone ######
+
+    # write Wishbone address
+    yield from jtag_read_write_reg(dut, WB_ADDR, 16, 0x18)
+
+    # write/read wishbone data
+    data = yield from jtag_read_write_reg(dut, WB_WRRD, 16, 0xfeef)
+    print ("wb write", hex(data))
+
+    # write Wishbone address
+    yield from jtag_read_write_reg(dut, WB_ADDR, 16, 0x18)
+
+    # write/read wishbone data
+    data = yield from jtag_read_write_reg(dut, WB_READ, 16, 0)
+    print ("wb read", hex(data))
+
+    ####### done - tell dmi_sim to stop (otherwise it won't) ########
+
+    dut.stop = True
+
+
+if __name__ == '__main__':
+    dut = DMITAP(ir_width=4)
+    dut.stop = False
+
+    # set up client-server on port 44843-something
+    dut.s = JTAGServer()
+    dut.c = JTAGClient()
+    dut.s.get_connection()
+
+    # rather than the client access the JTAG bus directly
+    # create an alternative that the client sets
+    dut.cbus = JTAGInterface()
+
+    iotypes = (IOType.In, IOType.Out, IOType.TriOut, IOType.InTriOut)
+    ios = [dut.add_io(iotype=iotype) for iotype in iotypes]
+    dut.sr = dut.add_shiftreg(ircode=4, length=3) # test loopback register
+
+    # create and connect wishbone SRAM (a quick way to do WB test)
+    dut.wb = dut.add_wishbone(ircodes=[WB_ADDR, WB_READ, WB_WRRD],
+                               address_width=16, data_width=16)
+    memory = Memory(width=16, depth=16)
+    sram = SRAM(memory=memory, bus=dut.wb)
+
+    # create DMI2JTAG (goes through to dmi_sim())
+    dut.dmi = dut.add_dmi(ircodes=[DMI_ADDR, DMI_READ, DMI_WRRD])
+
+    m = Module()
+    m.submodules.ast = dut
+    m.submodules.sram = sram
+    m.d.comb += dut.sr.i.eq(dut.sr.o) # loopback
+
+    sim = Simulator(m)
+    sim.add_clock(1e-6, domain="sync")      # standard clock
+
+    sim.add_sync_process(wrap(jtag_srv(dut))) # jtag server
+    sim.add_sync_process(wrap(jtag_sim(dut))) # actual jtag tester
+    sim.add_sync_process(wrap(dmi_sim(dut)))  # handles (pretends to be) DMI
+
+    with sim.write_vcd("dmi2jtag_test_srv.vcd"):
+        sim.run()
-- 
2.30.2