phy: add initial GW5RGMII (RGMII for Gowin Arora V series)

Tested on Sipeed Tang Mega 138K ES (GW5AT-138 ES).

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>

liteeth/phy/gw5rgmii.py

@@ -0,0 +1,197 @@
+#
+# This file is part of LiteEth.
+#
+# Copyright (c) 2023 Icenowy Zheng <uwu@icenowy.me>
+# Based on ecp5rgmii.py, which is:
+#   Copyright (c) 2019-2023 Florent Kermarrec <florent@enjoy-digital.fr>
+#   Copyright (c) 2020 Shawn Hoffman <godisgovernment@gmail.com>
+#
+# SPDX-License-Identifier: BSD-2-Clause
+
+# RGMII PHY for Gowin GW5A FPGA
+
+from migen import *
+from migen.genlib.resetsync import AsyncResetSynchronizer
+
+from litex.gen import *
+
+from litex.build.io import DDROutput, DDRInput
+
+from liteeth.common import *
+from liteeth.phy.common import *
+
+# LiteEth PHY RGMII TX -----------------------------------------------------------------------------
+
+class LiteEthPHYRGMIITX(LiteXModule):
+    def __init__(self, pads):
+        self.sink = sink = stream.Endpoint(eth_phy_description(8))
+
+        # # #
+
+        tx_ctl_oddrx1f  = Signal()
+        tx_data_oddrx1f = Signal(4)
+
+        self.specials += [
+            DDROutput(
+                clk = ClockSignal("eth_tx"),
+                i1  = sink.valid,
+                i2  = sink.valid,
+                o   = tx_ctl_oddrx1f,
+            ),
+            Instance("IODELAY",
+                p_DYN_DLY_EN   = "FALSE",
+                p_ADAPT_EN     = "FALSE",
+                p_C_STATIC_DLY = 0,
+                i_DI           = tx_ctl_oddrx1f,
+                o_DO           = pads.tx_ctl,
+            )
+        ]
+        for i in range(4):
+            self.specials += [
+                DDROutput(
+                    clk = ClockSignal("eth_tx"),
+                    i1  = sink.data[i],
+                    i2  = sink.data[4+i],
+                    o   = tx_data_oddrx1f[i],
+                ),
+                Instance("IODELAY",
+                    p_DYN_DLY_EN   = "FALSE",
+                    p_ADAPT_EN     = "FALSE",
+                    p_C_STATIC_DLY = 0,
+                    i_DI        = tx_data_oddrx1f[i],
+                    o_DO        = pads.tx_data[i],
+                )
+            ]
+        self.comb += sink.ready.eq(1)
+
+# LiteEth PHY RGMII RX -----------------------------------------------------------------------------
+
+class LiteEthPHYRGMIIRX(LiteXModule):
+    def __init__(self, pads, rx_delay=2e-9):
+        self.source = source = stream.Endpoint(eth_phy_description(8))
+
+        # # #
+
+        rx_delay_taps = int(rx_delay/12.5e-12) # 12.5ps per tap
+        assert rx_delay_taps < 256
+
+        rx_ctl_delayf  = Signal()
+        rx_ctl         = Signal()
+        rx_data_delayf = Signal(4)
+        rx_data        = Signal(8)
+
+        self.specials += [
+            Instance("IODELAY",
+                p_DYN_DLY_EN   = "FALSE",
+                p_ADAPT_EN     = "FALSE",
+                p_C_STATIC_DLY = rx_delay_taps,
+                i_DI           = pads.rx_ctl,
+                o_DO           = rx_ctl_delayf,
+            ),
+            DDRInput(
+                clk = ClockSignal("eth_rx"),
+                i   = rx_ctl_delayf,
+                o1  = rx_ctl,
+                o2  = Open()
+            )
+        ]
+        for i in range(4):
+            self.specials += [
+                Instance("IODELAY",
+                    p_DYN_DLY_EN   = "FALSE",
+                    p_ADAPT_EN     = "FALSE",
+                    p_C_STATIC_DLY = rx_delay_taps,
+                    i_DI           = pads.rx_data[i],
+                    o_DO           = rx_data_delayf[i]),
+                DDRInput(
+                    clk = ClockSignal("eth_rx"),
+                    i   = rx_data_delayf[i],
+                    o1  = rx_data[i],
+                    o2  = rx_data[i+4],
+                )
+            ]
+
+        rx_ctl_d = Signal()
+        self.sync += rx_ctl_d.eq(rx_ctl)
+
+        last = Signal()
+        self.comb += last.eq(~rx_ctl & rx_ctl_d)
+        self.sync += [
+            source.valid.eq(rx_ctl),
+            source.data.eq(rx_data)
+        ]
+        self.comb += source.last.eq(last)
+
+# LiteEth PHY RGMII CRG ----------------------------------------------------------------------------
+
+class LiteEthPHYRGMIICRG(LiteXModule):
+    def __init__(self, clock_pads, pads, with_hw_init_reset, tx_delay=2e-9, tx_clk=None):
+        self._reset = CSRStorage()
+
+        # # #
+
+        # RX Clock
+        self.cd_eth_rx = ClockDomain()
+        self.comb += self.cd_eth_rx.clk.eq(clock_pads.rx)
+
+        # TX Clock
+        self.cd_eth_tx = ClockDomain()
+        if isinstance(tx_clk, Signal):
+            self.comb += self.cd_eth_tx.clk.eq(tx_clk)
+        else:
+            self.comb += self.cd_eth_tx.clk.eq(self.cd_eth_rx.clk)
+
+        tx_delay_taps = int(tx_delay/12.5e-12) # 12.5ps per tap
+        assert tx_delay_taps < 256
+
+        self._txdelay_taps = CSRStorage(8, reset=tx_delay_taps)
+        eth_tx_clk_o = Signal()
+        self.specials += [
+            DDROutput(
+                clk = ClockSignal("eth_tx"),
+                i1  = 1,
+                i2  = 0,
+                o   = eth_tx_clk_o,
+            ),
+            Instance("IODELAY",
+                p_DYN_DLY_EN   = "TRUE",
+                p_ADAPT_EN     = "FALSE",
+                p_C_STATIC_DLY = tx_delay_taps,
+                i_DI           = eth_tx_clk_o,
+                i_DLYSTEP      = self._txdelay_taps.storage,
+                i_SDTAP        = 1,
+                o_DO           = clock_pads.tx,
+            )
+        ]
+
+        # Reset
+        self.reset = reset = Signal()
+        if with_hw_init_reset:
+            self.hw_reset = LiteEthPHYHWReset()
+            self.comb += reset.eq(self._reset.storage | self.hw_reset.reset)
+        else:
+            self.comb += reset.eq(self._reset.storage)
+        if hasattr(pads, "rst_n"):
+            self.comb += pads.rst_n.eq(~reset)
+        self.specials += [
+            AsyncResetSynchronizer(self.cd_eth_tx, reset),
+            AsyncResetSynchronizer(self.cd_eth_rx, reset),
+        ]
+
+
+class LiteEthPHYRGMII(LiteXModule):
+    dw          = 8
+    tx_clk_freq = 125e6
+    rx_clk_freq = 125e6
+    def __init__(self, clock_pads, pads, with_hw_init_reset=True,
+        tx_delay           = 2e-9,
+        rx_delay           = 2e-9,
+        tx_clk             = None,
+        ):
+        self.crg = LiteEthPHYRGMIICRG(clock_pads, pads, with_hw_init_reset, tx_delay, tx_clk)
+        self.tx  = ClockDomainsRenamer("eth_tx")(LiteEthPHYRGMIITX(pads))
+        self.rx  = ClockDomainsRenamer("eth_rx")(LiteEthPHYRGMIIRX(pads, rx_delay))
+        self.sink, self.source = self.tx.sink, self.rx.source
+
+        if hasattr(pads, "mdc"):
+            self.mdio = LiteEthPHYMDIO(pads)