test/test_csr.py

   1 # This file is Copyright (c) 2019 Florent Kermarrec <florent@enjoy-digital.fr>
   2 # License: BSD
   3
   4 import unittest
   5
   6 from migen import *
   7
   8 from litex.soc.interconnect import csr
   9 from litex.soc.interconnect import csr_bus
  10
  11
  12 def csr32_write(dut, adr, dat):
  13     for i in range(4):
  14         yield from dut.csr.write(adr + 3 - i, (dat >> 8*i) & 0xff)
  15
  16
  17 def csr32_read(dut, adr):
  18     dat = 0
  19     for i in range(4):
  20         dat |= ((yield from dut.csr.read(adr + 3 - i)) << 8*i)
  21     return dat
  22
  23
  24 class CSRModule(Module, csr.AutoCSR):
  25     def __init__(self):
  26         self._csr = csr.CSR()
  27         self._storage = csr.CSRStorage(32, reset=0x12345678, write_from_dev=True)
  28         self._status = csr.CSRStatus(32, reset=0x12345678)
  29
  30         # # #
  31
  32         # When csr is written:
  33         # - set storage to 0xdeadbeef
  34         # - set status to storage value
  35         self.comb += [
  36             If(self._csr.re,
  37                 self._storage.we.eq(1),
  38                 self._storage.dat_w.eq(0xdeadbeef)
  39             )
  40         ]
  41         self.sync += [
  42             If(self._csr.re,
  43                 self._status.status.eq(self._storage.storage)
  44             )
  45         ]
  46
  47
  48 class CSRDUT(Module):
  49     def address_map(self, name, memory):
  50             return {"csrmodule": 0}[name]
  51
  52     def __init__(self):
  53         self.csr = csr_bus.Interface()
  54         self.submodules.csrmodule = CSRModule()
  55         self.submodules.csrbankarray = csr_bus.CSRBankArray(
  56             self, self.address_map)
  57         self.submodules.csrcon = csr_bus.Interconnect(
  58             self.csr, self.csrbankarray.get_buses())
  59
  60 class TestCSR(unittest.TestCase):
  61     def test_csr_storage(self):
  62         def generator(dut):
  63             # check init value
  64             self.assertEqual(hex((yield from csr32_read(dut, 5))), hex(0x12345678))
  65
  66             # check writes
  67             yield from csr32_write(dut, 1, 0x5a5a5a5a)
  68             self.assertEqual(hex((yield from csr32_read(dut, 1))), hex(0x5a5a5a5a))
  69             yield from csr32_write(dut, 1, 0xa5a5a5a5)
  70             self.assertEqual(hex((yield from csr32_read(dut, 1))), hex(0xa5a5a5a5))
  71
  72             # check update from dev
  73             yield from dut.csr.write(0, 1)
  74             self.assertEqual(hex((yield from csr32_read(dut, 1))), hex(0xdeadbeef))
  75
  76         dut = CSRDUT()
  77         run_simulation(dut, generator(dut))
  78
  79     def test_csr_status(self):
  80         def generator(dut):
  81             # check init value
  82             self.assertEqual(hex((yield from csr32_read(dut, 1))), hex(0x12345678))
  83
  84             # check writes (no effect)
  85             yield from csr32_write(dut, 5, 0x5a5a5a5a)
  86             self.assertEqual(hex((yield from csr32_read(dut, 5))), hex(0x12345678))
  87             yield from csr32_write(dut, 5, 0xa5a5a5a5)
  88             self.assertEqual(hex((yield from csr32_read(dut, 5))), hex(0x12345678))
  89
  90             # check update from dev
  91             yield from dut.csr.write(0, 1)
  92             yield from dut.csr.write(0, 1)
  93             self.assertEqual(hex((yield from csr32_read(dut, 5))), hex(0xdeadbeef))
  94
  95         dut = CSRDUT()
  96         run_simulation(dut, generator(dut))
  97
  98     def test_csr_fields(self):
  99         def generator(dut):
 100             # check reset values
 101             self.assertEqual((yield dut._storage.fields.foo), 0xa)
 102             self.assertEqual((yield dut._storage.fields.bar), 0x5a)
 103             self.assertEqual((yield dut._storage.storage), 0x5a000a)
 104             yield
 105             yield
 106             self.assertEqual((yield dut._status.fields.foo), 0xa)
 107             self.assertEqual((yield dut._status.fields.bar), 0x5a)
 108
 109         class DUT(Module):
 110             def __init__(self):
 111                 self._storage = csr.CSRStorage(fields=[
 112                     csr.CSRField("foo", size=4, offset=0,  reset=0xa,  description="foo"),
 113                     csr.CSRField("bar", size=8, offset=16, reset=0x5a, description="bar")
 114                 ])
 115                 self._status = csr.CSRStatus(fields=[
 116                     csr.CSRField("foo", size=4, offset=4, description="foo"),
 117                     csr.CSRField("bar", size=8, offset=8, description="bar")
 118                 ])
 119                 self.comb += [
 120                     self._status.fields.foo.eq(self._storage.fields.foo),
 121                     self._status.fields.bar.eq(self._storage.fields.bar),
 122                 ]
 123         dut = DUT()
 124         run_simulation(dut, generator(dut))