#!/usr/bin/env python3

#
# This file is part of LiteX-Boards.
#
# Copyright (c) 2020 Antmicro <www.antmicro.com>
# Copyright (c) 2019 David Shah <dave@ds0.me>
# SPDX-License-Identifier: BSD-2-Clause

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

from litex.gen import LiteXModule

from litex_boards.platforms import xilinx_zcu104

from litex.soc.cores.clock import *
from litex.soc.integration.soc_core import *
from litex.soc.integration.builder import *
from litex.soc.cores.led import LedChaser
from litex.soc.cores.bitbang import I2CMaster

from litedram.modules import MTA4ATF51264HZ
from litedram.phy import usddrphy

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

class _CRG(LiteXModule):
    def __init__(self, platform, sys_clk_freq):
        self.rst       = Signal()
        self.cd_sys    = ClockDomain()
        self.cd_sys4x  = ClockDomain()
        self.cd_pll4x  = ClockDomain()
        self.cd_idelay = ClockDomain()

        # # #

        self.pll = pll = USMMCM(speedgrade=-2)
        self.comb += pll.reset.eq(self.rst)
        pll.register_clkin(platform.request("clk125"), 125e6)
        pll.create_clkout(self.cd_pll4x, sys_clk_freq*4, buf=None, with_reset=False)
        pll.create_clkout(self.cd_idelay, 500e6)
        platform.add_false_path_constraints(self.cd_sys.clk, pll.clkin) # Ignore sys_clk to pll.clkin path created by SoC's rst.

        self.specials += [
            Instance("BUFGCE_DIV",
                p_BUFGCE_DIVIDE=4,
                i_CE=1, i_I=self.cd_pll4x.clk, o_O=self.cd_sys.clk),
            Instance("BUFGCE",
                i_CE=1, i_I=self.cd_pll4x.clk, o_O=self.cd_sys4x.clk),
        ]

        self.idelayctrl = USIDELAYCTRL(cd_ref=self.cd_idelay, cd_sys=self.cd_sys)

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

class BaseSoC(SoCCore):
    def __init__(self, sys_clk_freq=int(125e6), with_led_chaser=True, **kwargs):
        platform = xilinx_zcu104.Platform()

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

        # SoCCore ----------------------------------------------------------------------------------
        SoCCore.__init__(self, platform, sys_clk_freq, ident="LiteX SoC on ZCU104", **kwargs)

        # DDR4 SDRAM -------------------------------------------------------------------------------
        if not self.integrated_main_ram_size:
            self.ddrphy = usddrphy.USPDDRPHY(platform.request("ddram"),
                memtype          = "DDR4",
                sys_clk_freq     = sys_clk_freq,
                iodelay_clk_freq = 500e6)
            self.add_sdram("sdram",
                phy           = self.ddrphy,
                module        = MTA4ATF51264HZ(sys_clk_freq, "1:4"),
                size          = 0x40000000,
                l2_cache_size = kwargs.get("l2_size", 8192)
            )

        # Leds -------------------------------------------------------------------------------------
        if with_led_chaser:
            self.leds = LedChaser(
                pads         = platform.request_all("user_led"),
                sys_clk_freq = sys_clk_freq)

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

def main():
    from litex.build.parser import LiteXArgumentParser
    parser = LiteXArgumentParser(platform=xilinx_zcu104.Platform, description="LiteX SoC on ZCU104")
    parser.add_target_argument("--sys-clk-freq", default=125e6,       help="System clock frequency.")
    args = parser.parse_args()

    soc = BaseSoC(
        sys_clk_freq = int(float(args.sys_clk_freq)),
        **parser.soc_core_argdict
    )
    builder = Builder(soc, **parser.builder_argdict)
    if args.build:
        builder.build(**parser.toolchain_argdict)

    if args.load:
        prog = soc.platform.create_programmer()
        prog.load_bitstream(builder.get_bitstream_filename(mode="sram"))

if __name__ == "__main__":
    main()