From 9d78eda9c4374f1cf714ddd0c07ceb17ee5459e0 Mon Sep 17 00:00:00 2001
From: Andrey Miroshnikov <andrey@technepisteme.xyz>
Date: Thu, 13 Jan 2022 22:30:32 +0000
Subject: [PATCH] Created and started making a basic IO mux block, unit test
 next.

---
 src/spec/iomux.py | 79 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 src/spec/iomux.py

diff --git a/src/spec/iomux.py b/src/spec/iomux.py
new file mode 100644
index 0000000..b7d6f3a
--- /dev/null
+++ b/src/spec/iomux.py
@@ -0,0 +1,79 @@
+"""This is the module used for multiplexing IO signals
+
+Documentation: https://libre-soc.org/docs/pinmux/temp_pinmux_info/
+Bug: https://bugs.libre-soc.org/show_bug.cgi?id=762
+"""
+#from random import randint
+from nmigen import Elaboratable, Module, Signal, Record, Array
+#from nmigen.utils import log2_int
+from nmigen.cli import rtlil
+#from soc.minerva.wishbone import make_wb_layout
+from nmutil.util import wrap
+#from soc.bus.test.wb_rw import wb_read, wb_write
+
+cxxsim = False
+if cxxsim:
+    from nmigen.sim.cxxsim import Simulator, Settle
+else:
+    from nmigen.sim import Simulator, Settle
+
+class IOMuxBlock(Elaboratable):
+
+    def __init__(self):
+        self.bank_sel = Signal()
+        
+        self.portin0 = {"i": Signal(), "o": Signal(), "oe": Signal()}
+        self.portin1 = {"i": Signal(), "o": Signal(), "oe": Signal()}
+        self.portout = {"i": Signal(), "o": Signal(), "oe": Signal()}
+
+    def elaborate(self, platform):
+        m = Module()
+        comb, sync = m.d.comb, m.d.sync
+        
+        bank_sel = self.bank_sel
+        portin0 = self.portin0
+        portin1 = self.portin1
+        portout = self.portout
+        # Connect IO Pad output port to one of the peripheral IOs
+        comb += portout["o"].eq(Mux(bank_sel, portin1["o"], portin0["o"]))
+        comb += portout["oe"].eq(Mux(bank_sel, portin1["oe"], portin0["oe"]))
+        
+        # Connect peripheral inputs to the IO pad input
+        comb += portin0["i"].eq(Mux(bank_sel, 0, portout["i"]))
+        comb += portin1["i"].eq(Mux(bank_sel, portout["i"], 0))
+
+        return m
+
+    def ports(self):
+        return list(self)
+
+def sim_iomux(dut):
+    # start by setting portin0
+    dut.portin0["o"].eq(1)
+    dut.portin0["oe"].eq(1)
+    yield
+    dut.portout["i"].eq(1)
+    
+    print("Finished the IO mux block test!")
+
+def test_iomux():
+
+    dut = IOMuxBlock()
+    vl = rtlil.convert(dut, ports=dut.ports())
+    with open("test_gpio.il", "w") as f:
+        f.write(vl)
+
+    m = Module()
+
+    #sim = Simulator(m)
+    #sim.add_clock(1e-6)
+
+    #sim.add_sync_process(wrap(sim_gpio(dut)))
+    #sim_writer = sim.write_vcd('test_gpio.vcd')
+    #with sim_writer:
+    #    sim.run()
+
+
+if __name__ == '__main__':
+    test_iomux()
+
-- 
2.30.2