#!/usr/bin/env python3

# This file is Copyright (c) 2018-2019 Florent Kermarrec <florent@enjoy-digital.fr>
# This file is Copyright (c) 2018-2019 David Shah <dave@ds0.me>
# License: BSD

import argparse

from migen import *
from migen.genlib.resetsync import AsyncResetSynchronizer

from litex_boards.platforms import versa_ecp5

from litex.build.lattice.trellis import trellis_args, trellis_argdict

from litex.soc.cores.clock import *
from litex.soc.integration.soc_sdram import *
from litex.soc.integration.builder import *

from litedram.modules import MT41K64M16
from litedram.phy import ECP5DDRPHY

from liteeth.phy.ecp5rgmii import LiteEthPHYRGMII
from liteeth.mac import LiteEthMAC

# CRG ----------------------------------------------------------------------------------------------

class _CRG(Module):
    def __init__(self, platform, sys_clk_freq):
        self.clock_domains.cd_init    = ClockDomain()
        self.clock_domains.cd_por     = ClockDomain(reset_less=True)
        self.clock_domains.cd_sys     = ClockDomain()
        self.clock_domains.cd_sys2x   = ClockDomain()
        self.clock_domains.cd_sys2x_i = ClockDomain(reset_less=True)

        # # #

        self.stop = Signal()

        # Clk / Rst
        clk100 = platform.request("clk100")
        rst_n  = platform.request("rst_n")
        platform.add_period_constraint(clk100, 1e9/100e6)

        # Power on reset
        por_count = Signal(16, reset=2**16-1)
        por_done  = Signal()
        self.comb += self.cd_por.clk.eq(ClockSignal())
        self.comb += por_done.eq(por_count == 0)
        self.sync.por += If(~por_done, por_count.eq(por_count - 1))

        # PLL
        self.submodules.pll = pll = ECP5PLL()
        pll.register_clkin(clk100, 100e6)
        pll.create_clkout(self.cd_sys2x_i, 2*sys_clk_freq)
        pll.create_clkout(self.cd_init, 25e6)
        self.specials += [
            Instance("ECLKSYNCB",
                i_ECLKI = self.cd_sys2x_i.clk,
                i_STOP  = self.stop,
                o_ECLKO = self.cd_sys2x.clk),
            Instance("CLKDIVF",
                p_DIV     = "2.0",
                i_ALIGNWD = 0,
                i_CLKI    = self.cd_sys2x.clk,
                i_RST     = self.cd_sys2x.rst,
                o_CDIVX   = self.cd_sys.clk),
            AsyncResetSynchronizer(self.cd_init, ~por_done | ~pll.locked | ~rst_n),
            AsyncResetSynchronizer(self.cd_sys,  ~por_done | ~pll.locked | ~rst_n)
        ]

# BaseSoC ------------------------------------------------------------------------------------------

class BaseSoC(SoCSDRAM):
    def __init__(self, sys_clk_freq=int(75e6), toolchain="diamond", **kwargs):
        platform = versa_ecp5.Platform(toolchain=toolchain)

        # SoCSDRAM ---------------------------------------------------------------------------------
        SoCSDRAM.__init__(self, platform, clk_freq=sys_clk_freq, **kwargs)

        # CRG --------------------------------------------------------------------------------------
        self.submodules.crg = _CRG(platform, sys_clk_freq)

        # DDR3 SDRAM -------------------------------------------------------------------------------
        if not self.integrated_main_ram_size:
            self.submodules.ddrphy = ECP5DDRPHY(
                platform.request("ddram"),
                sys_clk_freq=sys_clk_freq)
            self.add_csr("ddrphy")
            self.add_constant("ECP5DDRPHY", None)
            self.comb += self.crg.stop.eq(self.ddrphy.init.stop)
            sdram_module = MT41K64M16(sys_clk_freq, "1:2")
            self.register_sdram(self.ddrphy,
                geom_settings   = sdram_module.geom_settings,
                timing_settings = sdram_module.timing_settings)

# EthernetSoC --------------------------------------------------------------------------------------

class EthernetSoC(BaseSoC):
    mem_map = {
        "ethmac": 0xb0000000,
    }
    mem_map.update(BaseSoC.mem_map)

    def __init__(self, toolchain="diamond", **kwargs):
        BaseSoC.__init__(self, toolchain=toolchain, **kwargs)

        # Ethernet ---------------------------------------------------------------------------------
        # phy
        self.submodules.ethphy = LiteEthPHYRGMII(
            self.platform.request("eth_clocks"),
            self.platform.request("eth"))
        self.add_csr("ethphy")
        # mac
        self.submodules.ethmac = LiteEthMAC(phy=self.ethphy, dw=32,
            interface="wishbone", endianness=self.cpu.endianness)
        self.add_wb_slave(self.mem_map["ethmac"], self.ethmac.bus, 0x2000)
        self.add_memory_region("ethmac", self.mem_map["ethmac"], 0x2000, type="io")
        self.add_csr("ethmac")
        self.add_interrupt("ethmac")
        # timing constraints
        self.platform.add_period_constraint(self.ethphy.crg.cd_eth_rx.clk, 1e9/125e6)
        self.platform.add_period_constraint(self.ethphy.crg.cd_eth_tx.clk, 1e9/125e6)
        self.platform.add_false_path_constraints(
            self.crg.cd_sys.clk,
            self.ethphy.crg.cd_eth_rx.clk,
            self.ethphy.crg.cd_eth_tx.clk)

# Build --------------------------------------------------------------------------------------------

def main():
    parser = argparse.ArgumentParser(description="LiteX SoC on Versa ECP5")
    parser.add_argument("--gateware-toolchain", dest="toolchain", default="diamond",
        help='gateware toolchain to use, diamond (default) or  trellis')
    builder_args(parser)
    soc_sdram_args(parser)
    trellis_args(parser)
    parser.add_argument("--sys-clk-freq", default=75e6,
                        help="system clock frequency (default=75MHz)")
    parser.add_argument("--with-ethernet", action="store_true",
                        help="enable Ethernet support")
    args = parser.parse_args()

    cls = EthernetSoC if args.with_ethernet else BaseSoC
    soc = cls(toolchain=args.toolchain, sys_clk_freq=int(float(args.sys_clk_freq)), **soc_sdram_argdict(args))
    builder = Builder(soc, **builder_argdict(args))
    builder_kargs = {}
    if args.toolchain == "trellis":
        builder_kargs == trellis_argdict(args)
    builder.build(**builder_kargs)

if __name__ == "__main__":
    main()