test: add basic test_csr

test/test_csr.py

@@ -0,0 +1,93 @@
+import unittest
+
+from migen import *
+
+from litex.soc.interconnect import csr
+from litex.soc.interconnect import csr_bus
+
+
+def csr32_write(dut, adr, dat):
+    for i in range(4):
+        yield from dut.csr.write(adr + 3 - i, (dat >> 8*i) & 0xff)
+
+
+def csr32_read(dut, adr):
+    dat = 0
+    for i in range(4):
+        dat |= ((yield from dut.csr.read(adr + 3 - i)) << 8*i)
+    return dat
+
+
+class CSRModule(Module, csr.AutoCSR):
+    def __init__(self):
+        self._csr = csr.CSR()
+        self._storage = csr.CSRStorage(32, reset=0x12345678, write_from_dev=True)
+        self._status = csr.CSRStatus(32, reset=0x12345678)
+
+        # # #
+
+        # When csr is written:
+        # - set storage to 0xdeadbeef
+        # - set status to storage value
+        self.comb += [
+            If(self._csr.re,
+                self._storage.we.eq(1),
+                self._storage.dat_w.eq(0xdeadbeef)
+            )
+        ]
+        self.sync += [
+            If(self._csr.re,
+                self._status.status.eq(self._storage.storage)
+            )
+        ]
+
+
+class CSRDUT(Module):
+    def address_map(self, name, memory):
+            return {"csrmodule": 0}[name]
+
+    def __init__(self):
+        self.csr = csr_bus.Interface()
+        self.submodules.csrmodule = CSRModule()
+        self.submodules.csrbankarray = csr_bus.CSRBankArray(
+            self, self.address_map)
+        self.submodules.csrcon = csr_bus.Interconnect(
+            self.csr, self.csrbankarray.get_buses())
+
+class TestCSR(unittest.TestCase):
+    def test_csr_storage(self):
+        def generator(dut):
+            # check init value
+            self.assertEqual(hex((yield from csr32_read(dut, 5))), hex(0x12345678))
+
+            # check writes
+            yield from csr32_write(dut, 1, 0x5a5a5a5a)
+            self.assertEqual(hex((yield from csr32_read(dut, 1))), hex(0x5a5a5a5a))
+            yield from csr32_write(dut, 1, 0xa5a5a5a5)
+            self.assertEqual(hex((yield from csr32_read(dut, 1))), hex(0xa5a5a5a5))
+
+            # check update from dev
+            yield from dut.csr.write(0, 1)
+            self.assertEqual(hex((yield from csr32_read(dut, 1))), hex(0xdeadbeef))
+
+        dut = CSRDUT()
+        run_simulation(dut, generator(dut))
+
+    def test_csr_status(self):
+        def generator(dut):
+            # check init value
+            self.assertEqual(hex((yield from csr32_read(dut, 1))), hex(0x12345678))
+
+            # check writes (no effect)
+            yield from csr32_write(dut, 5, 0x5a5a5a5a)
+            self.assertEqual(hex((yield from csr32_read(dut, 5))), hex(0x12345678))
+            yield from csr32_write(dut, 5, 0xa5a5a5a5)
+            self.assertEqual(hex((yield from csr32_read(dut, 5))), hex(0x12345678))
+
+            # check update from dev
+            yield from dut.csr.write(0, 1)
+            yield from dut.csr.write(0, 1)
+            self.assertEqual(hex((yield from csr32_read(dut, 5))), hex(0xdeadbeef))
+
+        dut = CSRDUT()
+        run_simulation(dut, generator(dut))