Add DP83223-based PMD

This adds the integrated PMD module to be used with the DP83223. It
contains NRZI en/decoding as well as the I/O interfaces. The rx I/O was
added a while back, and the tx is just the I/O cell.

Signed-off-by: Sean Anderson <seanga2@gmail.com>

Makefile

@@ -102,6 +102,7 @@ MODULES += nrzi_encode
 MODULES += pcs_rx
 MODULES += pcs_tx
 MODULES += phy_core
+MODULES += pmd_dp83223
 MODULES += pmd_dp83223_rx
 MODULES += scramble
 

rtl/pmd_dp83223.v

@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: AGPL-3.0-Only
+/*
+ * Copyright (C) 2022 Sean Anderson <seanga2@gmail.com>
+ */
+
+`include "common.vh"
+`include "io.vh"
+
+`timescale 1ns/1ps
+
+module pmd_dp83223 (
+	input clk_250,
+	input clk_125,
+
+	/* I/O */
+	input indicate_data,
+	input signal_detect,
+	output reg request_data,
+
+	/* "PMD" */
+	input tx_data,
+	output [1:0] rx_data,
+	output [1:0] rx_data_valid,
+	output reg signal_status,
+
+	/* Control */
+	input loopback
+);
+
+	wire tx_nrzi;
+
+	nrzi_encode encoder (
+		.clk(clk_125),
+		.nrz(tx_data),
+		.nrzi(tx_nrzi)
+	);
+
+`ifdef SYNTHESIS
+	SB_IO #(
+		.PIN_TYPE(`PIN_OUTPUT_ALWAYS | `PIN_OUTPUT_REGISTERED),
+	) tx_data_pin (
+		.PACKAGE_PIN(request_data),
+		.OUTPUT_CLK(clk_125),
+		.D_OUT_0(loopback ? 1'b0 : tx_nrzi)
+	);
+`else
+	always @(posedge clk_125)
+		request_data <= loopback ? 1'b0 : tx_nrzi;
+`endif
+
+	wire signal_status_nrzi;
+	wire [1:0] rx_nrzi, rx_nrzi_valid;
+
+	pmd_dp83223_rx rx (
+		.clk_125(clk_125),
+		.clk_250(clk_250),
+
+		.signal_detect(signal_detect),
+		.indicate_data(indicate_data),
+
+		.signal_status(signal_status_nrzi),
+		.rx_data(rx_nrzi),
+		.rx_data_valid(rx_nrzi_valid)
+	);
+
+	nrzi_decode decoder (
+		.clk(clk_125),
+		.rst(loopback ? 1'b0 : !signal_status_nrzi),
+		.nrzi(loopback ? { tx_nrzi, 1'bX } : rx_nrzi),
+		.nrzi_valid(loopback ? 2'b01 : rx_nrzi_valid),
+		.nrz(rx_data),
+		.nrz_valid(rx_data_valid)
+	);
+
+	initial signal_status = 0;
+	always @(posedge clk_125)
+		signal_status <= loopback ? 1'b1 : signal_status_nrzi;
+
+endmodule

tb/pmd_dp83223.py

@@ -0,0 +1,77 @@
+# SPDX-License-Identifier: AGPL-3.0-Only
+# Copyright (C) 2022 Sean Anderson <seanga2@gmail.com>
+
+import random
+
+import cocotb
+from cocotb.clock import Clock
+from cocotb.triggers import ClockCycles, Combine, FallingEdge, Join, RisingEdge, Timer
+from cocotb.types import LogicArray
+
+from .nrzi_encode import nrzi_encode
+from .nrzi_decode import nrzi_decode
+from .pmd_dp83223_rx import check_bits
+from .util import alist, compare_lists, print_list_at
+
+@cocotb.test(timeout_time=3, timeout_unit='us')
+async def test_loopback(pmd):
+    rx_bits = [random.randrange(2) for _ in range(100)]
+    tx_bits = [random.randrange(2) for _ in range(100)]
+
+    pmd.loopback.value = 0
+    pmd.signal_detect.value = 0
+    pmd.tx_data.value = tx_bits[0]
+    await Timer(1)
+    await cocotb.start(Clock(pmd.clk_125, 8, units='ns').start())
+    await cocotb.start(Clock(pmd.clk_250, 4, units='ns').start())
+    
+    async def send_rx():
+        for bit in nrzi_encode(rx_bits):
+            pmd.signal_detect.value = 1
+            pmd.indicate_data.value = bit
+            await Timer(8, units='ns')
+        pmd.signal_detect.value = 0
+        pmd.indicate_data.value = LogicArray('X')
+
+    async def send_tx():
+        for bit in tx_bits:
+            pmd.tx_data.value = bit
+            await FallingEdge(pmd.clk_125)
+
+    async def recv_tx(delay):
+        async def bits():
+            await ClockCycles(pmd.clk_125, delay)
+            for _ in range(len(tx_bits)):
+                await RisingEdge(pmd.clk_125)
+                yield pmd.request_data.value
+
+        compare_lists(tx_bits, await alist(nrzi_decode(bits())))
+
+    async def test_normal(delay=2):
+        await cocotb.start(send_rx())
+        await cocotb.start(send_tx())
+        rx_task = await cocotb.start(check_bits(pmd, rx_bits))
+        tx_task = await cocotb.start(recv_tx(delay))
+
+        await Combine(Join(rx_task), Join(tx_task))
+
+    await test_normal()
+
+    async def loopback_monitor():
+        await ClockCycles(pmd.clk_125, 2)
+        while pmd.loopback.value:
+            assert not pmd.request_data.value
+            await RisingEdge(pmd.clk_125)
+
+    tx_task = await cocotb.start(send_rx())
+    await cocotb.start(send_tx())
+    rx_task = await cocotb.start(check_bits(pmd, tx_bits))
+    loop_task = await cocotb.start(loopback_monitor())
+    pmd.loopback.value = 1
+
+    await Join(tx_task)
+    pmd.loopback.value = 0
+    await Join(rx_task)
+    loop_task.kill()
+
+    await test_normal(1)