#!/usr/bin/env python3

# This file is Copyright (c) Greg Davill <greg.davill@gmail.com>
# License: BSD

import argparse

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

from litex_boards.platforms import orangecrab

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.clock_domains.cd_sys2x_eb = ClockDomain(reset_less=True)


        # # #

        self.stop = Signal()

        # Clk / Rst
        clk48 = platform.request("clk48")
        platform.add_period_constraint(clk48, 1e9/48e6)

        # 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
        sys2x_clk_ecsout = Signal()
        self.submodules.pll = pll = ECP5PLL()
        pll.register_clkin(clk48, 48e6)
        pll.create_clkout(self.cd_sys2x_i, 2*sys_clk_freq)
        pll.create_clkout(self.cd_init, 24e6)
        self.specials += [
            Instance("ECLKBRIDGECS",
                i_CLK0   = self.cd_sys2x_i.clk,
                i_SEL    = 0,
                o_ECSOUT = sys2x_clk_ecsout,
            ),
            Instance("ECLKSYNCB",
                i_ECLKI = sys2x_clk_ecsout,
                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, sys_clk_freq=int(48e6), toolchain="trellis", **kwargs):
        platform = orangecrab.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 -------------------------------------------------------------------------------
        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 OrangeCrab")
    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)
    parser.add_argument("--sys-clk-freq", default=48e6,
                        help="system clock frequency (default=48MHz)")
    args = parser.parse_args()

    soc = BaseSoC(toolchain=args.toolchain, sys_clk_freq=int(float(args.sys_clk_freq)), **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()