From: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Date: Sat, 1 May 2021 19:31:08 +0000 (+0100)
Subject: store data in microwatt dcache goes in one cycle AFTER valid is set
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=fb58a927888305a929cbff4dcae2234ede55bb60;p=soc.git

store data in microwatt dcache goes in one cycle AFTER valid is set
---

diff --git a/src/soc/fu/mmu/fsm.py b/src/soc/fu/mmu/fsm.py
index a31b8100..d7d52f37 100644
--- a/src/soc/fu/mmu/fsm.py
+++ b/src/soc/fu/mmu/fsm.py
@@ -47,11 +47,16 @@ class LoadStore1(PortInterfaceBase):
         # TODO, convert dcache wb_in/wb_out to "standard" nmigen Wishbone bus
         self.dbus = Record(make_wb_layout(pspec))
 
+        # for creating a single clock blip to DCache
+        self.d_valid = Signal()
+        self.d_validblip = Signal()
+
     def set_wr_addr(self, m, addr, mask):
         #m.d.comb += self.l_in.valid.eq(1)
         #m.d.comb += self.l_in.addr.eq(addr)
         #m.d.comb += self.l_in.load.eq(0)
-        m.d.comb += self.d_in.valid.eq(1)
+        m.d.comb += self.d_valid.eq(1)
+        m.d.comb += self.d_in.valid.eq(self.d_validblip)
         m.d.comb += self.d_in.load.eq(0)
         m.d.comb += self.d_in.byte_sel.eq(mask)
         # set phys addr on both units
@@ -63,7 +68,8 @@ class LoadStore1(PortInterfaceBase):
         #m.d.comb += self.l_in.valid.eq(1)
         #m.d.comb += self.l_in.load.eq(1)
         #m.d.comb += self.l_in.addr.eq(addr)
-        m.d.comb += self.d_in.valid.eq(1)
+        m.d.comb += self.d_valid.eq(1)
+        m.d.comb += self.d_in.valid.eq(self.d_validblip)
         m.d.comb += self.d_in.load.eq(1)
         m.d.comb += self.d_in.byte_sel.eq(mask)
         m.d.comb += self.d_in.addr.eq(addr)
@@ -72,7 +78,7 @@ class LoadStore1(PortInterfaceBase):
         return None #FIXME return value
 
     def set_wr_data(self, m, data, wen):
-        m.d.comb += self.d_in.data.eq(data)
+        m.d.sync += self.d_in.data.eq(data) # one cycle **AFTER** valid raised
         # TODO set wen
         st_ok = Const(1, 1)
         return st_ok
@@ -160,6 +166,9 @@ class LoadStore1(PortInterfaceBase):
         if hasattr(dbus, "stall"):
             comb += dcache.wb_in.stall.eq(dbus.stall)
 
+        # create a blip (single pulse) on valid read/write request
+        m.d.comb += self.d_validblip.eq(rising_edge(m, self.d_valid))
+
         return m
 
     def ports(self):
diff --git a/src/soc/simple/test/test_issuer_mmu.py b/src/soc/simple/test/test_issuer_mmu.py
index bafcf3b1..f35dbe15 100644
--- a/src/soc/simple/test/test_issuer_mmu.py
+++ b/src/soc/simple/test/test_issuer_mmu.py
@@ -37,12 +37,12 @@ if __name__ == "__main__":
     suite = unittest.TestSuite()
     #suite.addTest(TestRunner(GeneralTestCases.test_data, svp64=svp64,
     #                          microwatt_mmu=True))
-    suite.addTest(TestRunner(MMUTestCase().test_data, svp64=svp64,
-                              microwatt_mmu=True))
+    #suite.addTest(TestRunner(MMUTestCase().test_data, svp64=svp64,
+    #                          microwatt_mmu=True))
 
     # without ROM set
-    suite.addTest(TestRunner(MMUTestCaseROM().test_data, svp64=svp64,
-                              microwatt_mmu=True))
+    #suite.addTest(TestRunner(MMUTestCaseROM().test_data, svp64=svp64,
+    #                          microwatt_mmu=True))
 
     # LD/ST tests should all still work
     suite.addTest(TestRunner(LDSTTestCase().test_data, svp64=svp64,