#!/usr/bin/env python3

# This file is Copyright (c) 2019 Florent Kermarrec <florent@enjoy-digital.fr>
# License: BSD

import argparse
import sys

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

from litex_boards.platforms import camlink_4k

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

# 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
        clk27 = platform.request("clk27")
        platform.add_period_constraint(clk27, 1e9/27e6)

        # 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(clk27, 27e6)
        pll.create_clkout(self.cd_sys2x_i, 2*sys_clk_freq)
        pll.create_clkout(self.cd_init, 27e6)
        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),
            AsyncResetSynchronizer(self.cd_sys, ~por_done | ~pll.locked)
        ]

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

class BaseSoC(SoCSDRAM):
    def __init__(self, toolchain="diamond", **kwargs):
        platform     = camlink_4k.Platform(toolchain=toolchain)
        sys_clk_freq = int(81e6)

        # 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)

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

def main():
    parser = argparse.ArgumentParser(description="LiteX SoC on Cam Link 4K")
    parser.add_argument("--gateware-toolchain", dest="toolchain", default="trellis",
        help='gateware toolchain to use, trellis (default) or diamond')
    builder_args(parser)
    soc_sdram_args(parser)
    trellis_args(parser)
    args = parser.parse_args()

    soc = BaseSoC(toolchain=args.toolchain, **soc_sdram_argdict(args))
    builder = Builder(soc, **builder_argdict(args))
    builder_kargs = trellis_argdict(args) if args.toolchain == "trellis" else {}
    builder.build(**builder_kargs)

if __name__ == "__main__":
    main()