#!/usr/bin/env python3

# This file is Copyright (c) 2020 Antmicro <www.antmicro.com>
# License: BSD

import argparse

from migen import *
from migen.genlib.io import CRG

from litex_boards.platforms import mercury_xu5

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

from litedram.modules import MT40A256M16
from litedram.phy import usddrphy

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

class _CRG(Module):
    def __init__(self, platform, sys_clk_freq):
        self.clock_domains.cd_sys    = ClockDomain()
        self.clock_domains.cd_sys4x  = ClockDomain(reset_less=True)
        self.clock_domains.cd_pll4x  = ClockDomain(reset_less=True)
        self.clock_domains.cd_clk400 = ClockDomain()
        self.clock_domains.cd_ic     = ClockDomain()

        self.submodules.pll = pll = USMMCM(speedgrade=-1)
        pll.register_clkin(platform.request("clk100"), 100e6)

        pll.create_clkout(self.cd_pll4x, sys_clk_freq*4, buf=None, with_reset=False)
        pll.create_clkout(self.cd_clk400, 400e6, with_reset=False)

        self.specials += [
            Instance("BUFGCE_DIV", name="main_bufgce_div",
                p_BUFGCE_DIVIDE=4,
                i_CE=1, i_I=self.cd_pll4x.clk, o_O=self.cd_sys.clk),
            Instance("BUFGCE", name="main_bufgce",
                i_CE=1, i_I=self.cd_pll4x.clk, o_O=self.cd_sys4x.clk),
            AsyncResetSynchronizer(self.cd_clk400, ~pll.locked),
        ]

        ic_reset_counter = Signal(max=64, reset=63)
        ic_reset = Signal(reset=1)
        self.sync.clk400 += \
            If(ic_reset_counter != 0,
                ic_reset_counter.eq(ic_reset_counter - 1)
            ).Else(
                ic_reset.eq(0)
            )
        ic_rdy = Signal()
        ic_rdy_counter = Signal(max=64, reset=63)
        self.cd_sys.rst.reset = 1
        self.comb += self.cd_ic.clk.eq(self.cd_sys.clk)
        self.sync.ic += [
            If(ic_rdy,
                If(ic_rdy_counter != 0,
                    ic_rdy_counter.eq(ic_rdy_counter - 1)
                ).Else(
                    self.cd_sys.rst.eq(0)
                )
            )
        ]
        self.specials += [
            Instance("IDELAYCTRL", p_SIM_DEVICE="ULTRASCALE",
                     i_REFCLK=ClockSignal("clk400"), i_RST=ic_reset,
                     o_RDY=ic_rdy),
            AsyncResetSynchronizer(self.cd_ic, ic_reset)
        ]

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

class BaseSoC(SoCSDRAM):
    def __init__(self, sys_clk_freq=int(100e6), **kwargs):
        platform = mercury_xu5.Platform()

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

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

        # DDR4 SDRAM -------------------------------------------------------------------------------
        if not self.integrated_main_ram_size:
            self.submodules.ddrphy = usddrphy.USDDRPHY(platform.request("ddram"),
                memtype          = "DDR4",
                sim_device       = "ULTRASCALE_PLUS",
                iodelay_clk_freq = 400e6,
                cmd_latency      = 1,
                sys_clk_freq     = sys_clk_freq)
            self.add_csr("ddrphy")
            self.add_constant("USDDRPHY", None)
            sdram_module = MT40A256M16(sys_clk_freq, "1:4")
            self.register_sdram(self.ddrphy,
                geom_settings       = sdram_module.geom_settings,
                timing_settings     = sdram_module.timing_settings)

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

def main():
    parser = argparse.ArgumentParser(description="LiteX SoC on Enclustra's Mercury XU5")
    builder_args(parser)
    soc_sdram_args(parser)
    args = parser.parse_args()

    soc = BaseSoC(**soc_sdram_argdict(args))
    builder = Builder(soc, **builder_argdict(args))
    builder.build()


if __name__ == "__main__":
    main()