From 4c18c991bca5482a2650889db9c9a756666a1274 Mon Sep 17 00:00:00 2001
From: Florent Kermarrec <florent@enjoy-digital.fr>
Date: Fri, 5 Jul 2019 18:30:34 +0200
Subject: [PATCH] cores: add ICAP core (tested with reconfiguration commands)

---
 litex/soc/cores/icap.py | 76 +++++++++++++++++++++++++++++++++++++++++
 test/test_icap.py       | 27 +++++++++++++++
 2 files changed, 103 insertions(+)
 create mode 100644 litex/soc/cores/icap.py
 create mode 100644 test/test_icap.py

diff --git a/litex/soc/cores/icap.py b/litex/soc/cores/icap.py
new file mode 100644
index 000000000..d607e3566
--- /dev/null
+++ b/litex/soc/cores/icap.py
@@ -0,0 +1,76 @@
+# This file is Copyright (c) 2019 Florent Kermarrec <florent@enjoy-digital.fr>
+# License: BSD
+
+from migen import *
+
+from migen.genlib.misc import timeline
+from migen.genlib.cdc import PulseSynchronizer
+
+from litex.soc.interconnect.csr import *
+
+# Xilinx 7-series ----------------------------------------------------------------------------------
+
+class ICAP(Module, AutoCSR):
+    """ICAP
+
+    Allow sending commands to ICAPE2 of Xilinx 7-Series FPGAs, the bistream can for example be
+    reloaded from SPI Flash by writing 0x00000000 at address @0x4.
+    """
+    def __init__(self, simulation=False):
+        self.addr = CSRStorage(5)
+        self.data = CSRStorage(32)
+        self.send = CSR()
+        self.done = CSRStatus(reset=1)
+
+        # # #
+
+        # Create slow icap clk (sys_clk/2) ---------------------------------------------------------
+        self.clock_domains.cd_icap = ClockDomain()
+        icap_clk_counter = Signal(4)
+        self.sync += icap_clk_counter.eq(icap_clk_counter + 1)
+        self.sync += self.cd_icap.clk.eq(icap_clk_counter[3])
+
+        # Resychronize send pulse to icap domain ---------------------------------------------------
+        ps_send = PulseSynchronizer("sys", "icap")
+        self.submodules += ps_send
+        self.comb += [ps_send.i.eq(self.send.re)]
+
+        # generate icap bitstream write sequence
+        _csib = Signal(reset=1)
+        _i = Signal(32)
+        _addr = self.addr.storage << 13
+        _data = self.data.storage
+        self.sync.icap += [
+            _i.eq(0xffffffff), # dummy
+            timeline(ps_send.o, [
+                (1,  [_csib.eq(1), self.done.status.eq(0)]),
+                (2,  [_csib.eq(0), _i.eq(0x20000000)]),         # noop
+                (3,  [_csib.eq(0), _i.eq(0xaa995566)]),         # sync word
+                (4,  [_csib.eq(0), _i.eq(0x20000000)]),         # noop
+                (5,  [_csib.eq(0), _i.eq(0x20000000)]),         # noop
+                (6,  [_csib.eq(0), _i.eq(0x30000001 | _addr)]), # write command
+                (7,  [_csib.eq(0), _i.eq(_data)]),              # write value
+                (8,  [_csib.eq(0), _i.eq(0x20000000)]),         # noop
+                (9,  [_csib.eq(0), _i.eq(0x20000000)]),         # noop
+                (10, [_csib.eq(0), _i.eq(0x30008001)]),         # write to cmd register
+                (11, [_csib.eq(0), _i.eq(0x0000000d)]),         # desync command
+                (12, [_csib.eq(0), _i.eq(0x20000000)]),         # noop
+                (13, [_csib.eq(0), _i.eq(0x20000000)]),         # noop
+                (14, [_csib.eq(1), self.done.status.eq(1)]),
+            ])
+        ]
+
+        self._csib = _csib
+        self._i = _i
+
+        # icap instance
+        if not simulation:
+            self.specials += [
+                Instance("ICAPE2",
+                    p_ICAP_WIDTH="X32",
+                    i_CLK=ClockSignal("icap"),
+                    i_CSIB=_csib,
+                    i_RDWRB=0,
+                    i_I=Cat(*[_i[8*i:8*(i+1)][::-1] for i in range(4)]),
+                )
+            ]
diff --git a/test/test_icap.py b/test/test_icap.py
new file mode 100644
index 000000000..444451764
--- /dev/null
+++ b/test/test_icap.py
@@ -0,0 +1,27 @@
+# This file is Copyright (c) 2019 Florent Kermarrec <florent@enjoy-digital.fr>
+# License: BSD
+
+import unittest
+
+from migen import *
+
+from litex.soc.cores.icap import ICAP
+
+
+class TestICAP(unittest.TestCase):
+    def test_reload(self):
+        def generator(dut):
+            yield dut.addr.storage.eq(0x4)
+            yield dut.data.storage.eq(0xf)
+            for i in range(16):
+                yield
+            yield dut.send.re.eq(1)
+            yield
+            yield dut.send.re.eq(0)
+            for i in range(256):
+                yield
+
+        dut = ICAP(simulation=True)
+        clocks = {"sys": 10,
+                  "icap":20}
+        run_simulation(dut, generator(dut), clocks, vcd_name="icap.vcd")