Create atlantic.py

atlantic JTAG uart for Intel FPGA's, working and tested on Intel C10LP EK

litex/soc/cores/atlantic.py

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+# This file is Copyright (c) 2019 Antti Lukats <antti.lukats@gmail.com>
+
+# This file is Copyright (c) 2014 Yann Sionneau <ys@m-labs.hk>
+# This file is Copyright (c) 2015-2018 Florent Kermarrec <florent@enjoy-digital.fr>
+# This file is Copyright (c) 2015 Sebastien Bourdeauducq <sb@m-labs.hk>
+# This file is Copyright (c) 2018 Tim 'mithro' Ansell <me@mith.ro>
+# License: BSD
+
+from migen import *
+from migen.genlib.record import Record
+
+from litex.soc.interconnect.csr import *
+from litex.soc.interconnect.csr_eventmanager import *
+
+class JTAG_atlantic(Module):
+    def __init__(self,
+                 tx_fifo_depth=32,
+                 rx_fifo_depth=32):
+        # todo fifo depth calculation?     
+
+        self.tx_valid = Signal()
+        self.tx_ready = Signal()
+        self.tx_data  = Signal(8)
+
+        self.rx_valid = Signal()
+        self.rx_ready = Signal()
+        self.rx_pause = Signal()
+        self.rx_data  = Signal(8)
+
+        self.specials += Instance("alt_jtag_atlantic",
+            #p_INSTANCE_ID             =  0, # should be 0, can not be "0" or 1'b0 !
+            p_LOG2_RXFIFO_DEPTH       = "5", # should be INTEGR, but not recognized by migen?
+            p_LOG2_TXFIFO_DEPTH       = "5", # "<>" is OK, can not be left out
+            p_SLD_AUTO_INSTANCE_INDEX = "YES",
+            i_clk     = ClockSignal("sys"), 
+            i_rst_n   = ~ResetSignal("sys"),
+            # we transmit here - our tx
+            i_r_dat   = self.tx_data,
+            i_r_val   = self.tx_valid,
+            o_r_ena   = self.tx_ready,
+            # transmit part of uart - our RX
+            o_t_dat   = self.rx_data,
+            i_t_dav   = self.rx_ready,
+            o_t_ena   = self.rx_valid,
+            o_t_pause = self.rx_pause
+        )
+
+
+# Altera Atlantic JTAG UART ----------------------------------------------------------------------------------------
+
+class UART_atlantic(Module, AutoCSR):
+    def __init__(self, platform,
+                 tx_fifo_depth=32,
+                 rx_fifo_depth=32):
+        self._rxtx = CSR(8)
+        self._txfull = CSRStatus()
+        self._rxempty = CSRStatus()
+
+        self.submodules.ev = EventManager()
+        self.ev.tx = EventSourceProcess()
+        self.ev.rx = EventSourceProcess()
+        self.ev.finalize()
+
+        #
+        self.submodules.jtag = JTAG_atlantic(tx_fifo_depth, rx_fifo_depth)
+
+        # TX is working, can be simplified maybe?
+        tx_data = Signal(8)
+        tx_valid = Signal()
+        tx_pending = Signal()
+        tx_busy = Signal()
+
+        self.sync += [
+            If(self._rxtx.re,
+                tx_data.eq(self._rxtx.r), # latch tx data
+                tx_pending.eq(1),         # 
+                tx_busy.eq(1),            # 
+            ),
+            If(tx_pending & self.jtag.tx_ready,
+                tx_valid.eq(1),           # 
+                tx_pending.eq(0)
+            ),
+            If(tx_valid & ~self.jtag.tx_ready,
+                tx_valid.eq(0),         # clear valid
+                tx_busy.eq(0),          # 
+            ),
+        ]
+
+        self.comb += [
+            self.jtag.tx_valid.eq(tx_valid),
+            self.jtag.tx_data.eq(tx_data),
+            self._txfull.status.eq(~self.jtag.tx_ready | tx_busy),
+            # Generate TX IRQ when tx_fifo becomes non-full
+            self.ev.tx.trigger.eq(~self.jtag.tx_ready | tx_busy)
+        ]
+
+
+        # RX
+        rx_data = Signal(8)
+        rx_ready = Signal(reset=1)
+        rx_pending = Signal(reset=0) 
+
+        self.sync += [
+            If(self.jtag.rx_valid & rx_ready,
+                rx_data.eq(self.jtag.rx_data),
+                rx_pending.eq(1),
+                rx_ready.eq(0) 
+            ),
+            If(self.ev.rx.clear,
+               rx_pending.eq(0),
+               rx_ready.eq(1),
+            ),
+
+        ]
+
+        self.comb += [
+            self._rxempty.status.eq(~rx_pending),
+            self._rxtx.w.eq(rx_data),
+            self.jtag.rx_ready.eq(rx_ready),
+            # Generate RX IRQ when rx_fifo becomes non-empty
+            self.ev.rx.trigger.eq(~rx_pending)
+        ]
+#
+# todo atlantic wishbone bridge?
+#
+
+
+