From 2f5feeceae2f50db56ea8cc52c2d91e59fc97bec Mon Sep 17 00:00:00 2001
From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Tue, 22 Sep 2020 13:01:00 +0100
Subject: [PATCH] add jtag interface to issuer_verilog

---
 src/soc/debug/dmi.py             |  8 ++++++++
 src/soc/debug/dmi2jtag.py        |  3 +++
 src/soc/debug/jtag.py            |  8 +++++++-
 src/soc/simple/issuer.py         | 17 ++++++++++++++++-
 src/soc/simple/issuer_verilog.py |  1 +
 5 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/soc/debug/dmi.py b/src/soc/debug/dmi.py
index 5875813c..39ea799b 100644
--- a/src/soc/debug/dmi.py
+++ b/src/soc/debug/dmi.py
@@ -61,6 +61,14 @@ class DMIInterface(RecordObject):
         self.we_i   = Signal()    # DMI write-enable
         self.ack_o  = Signal()    # DMI ack request
 
+    def connect_to(self, other):
+        return [self.addr_i.eq(other.addr_i),
+                self.req_i.eq(other.req_i),
+                self.we_i.eq(other.we_i),
+                self.din.eq(other.din),
+                other.ack_o.eq(self.ack_o),
+                other.dout.eq(self.dout),
+                ]
 
 class DbgReg(RecordObject):
     def __init__(self, name):
diff --git a/src/soc/debug/dmi2jtag.py b/src/soc/debug/dmi2jtag.py
index d178c14a..96b13b2d 100644
--- a/src/soc/debug/dmi2jtag.py
+++ b/src/soc/debug/dmi2jtag.py
@@ -133,6 +133,9 @@ class DMITAP(TAP):
                     dmi.we_i.eq(ds.ongoing("WRRD")),
                 ]
 
+    def external_ports(self):
+        return [self.bus.tdo, self.bus.tdi, self.bus.tms, self.bus.tck]
+
 
 if __name__ == '__main__':
     dut = DMITAP(ir_width=4)
diff --git a/src/soc/debug/jtag.py b/src/soc/debug/jtag.py
index 9e28e47b..67dadd7b 100644
--- a/src/soc/debug/jtag.py
+++ b/src/soc/debug/jtag.py
@@ -19,7 +19,8 @@ class JTAG(DMITAP):
 
         # create and connect wishbone 
         self.wb = self.add_wishbone(ircodes=[5, 6, 7],
-                                   address_width=29, data_width=64)
+                                   address_width=29, data_width=64,
+                                   name="jtag_wb")
 
         # create DMI2JTAG (goes through to dmi_sim())
         self.dmi = self.add_dmi(ircodes=[8, 9, 10])
@@ -27,6 +28,11 @@ class JTAG(DMITAP):
     def elaborate(self, platform):
         return super().elaborate(platform)
 
+    def external_ports(self):
+        ports = super().external_ports()
+        ports += list(self.wb.fields.values())
+        return ports
+
 
 if __name__ == '__main__':
     dut = JTAG()
diff --git a/src/soc/simple/issuer.py b/src/soc/simple/issuer.py
index f0b2b1bf..332dda80 100644
--- a/src/soc/simple/issuer.py
+++ b/src/soc/simple/issuer.py
@@ -32,6 +32,7 @@ from soc.config.test.test_loadstore import TestMemPspec
 from soc.config.ifetch import ConfigFetchUnit
 from soc.decoder.power_enums import MicrOp
 from soc.debug.dmi import CoreDebug, DMIInterface
+from soc.debug.jtag import JTAG
 from soc.config.state import CoreState
 from soc.interrupts.xics import XICS_ICP, XICS_ICS
 from soc.bus.simple_gpio import SimpleGPIO
@@ -77,6 +78,11 @@ class TestIssuer(Elaboratable):
         # DMI interface
         self.dbg = CoreDebug()
 
+        # JTAG interface
+        self.jtag_en = hasattr(pspec, "debug") and pspec.debug == 'jtag'
+        if self.jtag_en:
+            self.jtag = JTAG()
+
         # instruction go/monitor
         self.pc_o = Signal(64, reset_less=True)
         self.pc_i = Data(64, "pc_i") # set "ok" to indicate "please change me"
@@ -109,6 +115,9 @@ class TestIssuer(Elaboratable):
         m.submodules.core = core = DomainRenamer("coresync")(self.core)
         m.submodules.imem = imem = self.imem
         m.submodules.dbg = dbg = self.dbg
+        if self.jtag_en:
+            m.submodules.jtag = jtag = self.jtag
+            comb += dbg.dmi.connect_to(jtag.dmi)
 
         cur_state = self.cur_state
 
@@ -400,7 +409,13 @@ class TestIssuer(Elaboratable):
         ports += [self.pc_o, self.memerr_o, self.core_bigendian_i, self.busy_o,
                   ClockSignal(), ResetSignal(),
                 ]
-        ports += list(self.dbg.dmi.ports())
+
+        if self.jtag_en:
+            ports += list(self.jtag.external_ports())
+        else:
+            # don't add DMI if JTAG is enabled
+            ports += list(self.dbg.dmi.ports())
+
         ports += list(self.imem.ibus.fields.values())
         ports += list(self.core.l0.cmpi.lsmem.lsi.slavebus.fields.values())
 
diff --git a/src/soc/simple/issuer_verilog.py b/src/soc/simple/issuer_verilog.py
index 8cd713f8..820e5fd3 100644
--- a/src/soc/simple/issuer_verilog.py
+++ b/src/soc/simple/issuer_verilog.py
@@ -29,6 +29,7 @@ if __name__ == '__main__':
                          #wb_data_wid=32,
                          xics=True,
                          gpio=False, # for test purposes
+                         debug="jtag", # set to jtag or dmi
                          units=units)
 
     dut = TestIssuer(pspec)
-- 
2.30.2