#!/usr/bin/env python3

#
# This file is part of LiteX-Boards.
#
# Copyright (c) 2019 Arnaud Durand <arnaud.durand@unifr.ch>
# SPDX-License-Identifier: BSD-2-Clause

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

from litex_boards.platforms import lattice_ecp5_evn

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

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

class _CRG(Module):
    def __init__(self, platform, sys_clk_freq, x5_clk_freq):
        self.rst = Signal()
        self.clock_domains.cd_sys = ClockDomain()

        # # #

        # Clk / Rst.
        clk = clk12 = platform.request("clk12")
        rst_n = platform.request("rst_n")
        if x5_clk_freq is not None:
            clk = clk50 = platform.request("ext_clk50")
            self.comb += platform.request("ext_clk50_en").eq(1)
            platform.add_period_constraint(clk50, 1e9/x5_clk_freq)

        # PLL.
        self.submodules.pll = pll = ECP5PLL()
        self.comb += pll.reset.eq(~rst_n | self.rst)
        pll.register_clkin(clk, x5_clk_freq or 12e6)
        pll.create_clkout(self.cd_sys, sys_clk_freq)

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

class BaseSoC(SoCCore):
    def __init__(self, sys_clk_freq=int(50e6), x5_clk_freq=None, toolchain="trellis",
                 with_led_chaser=True, **kwargs):
        platform = lattice_ecp5_evn.Platform(toolchain=toolchain)

        # CRG --------------------------------------------------------------------------------------
        self.submodules.crg = _CRG(platform, sys_clk_freq, x5_clk_freq)

        # SoCCore ----------------------------------------------------------------------------------
        SoCCore.__init__(self, platform, sys_clk_freq, ident="LiteX SoC on ECP5 Evaluation Board", **kwargs)

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

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

def main():
    from litex.soc.integration.soc import LiteXSoCArgumentParser
    parser = LiteXSoCArgumentParser(description="LiteX SoC on ECP5 Evaluation Board")
    target_group = parser.add_argument_group(title="Target options")
    target_group.add_argument("--build",        action="store_true", help="Build bitstream.")
    target_group.add_argument("--load",         action="store_true", help="Load bitstream.")
    target_group.add_argument("--toolchain",    default="trellis",   help="FPGA toolchain (trellis or diamond).")
    target_group.add_argument("--sys-clk-freq", default=60e6,        help="System clock frequency.")
    target_group.add_argument("--x5-clk-freq",  type=int,            help="Use X5 oscillator as system clock at the specified frequency.")
    builder_args(parser)
    soc_core_args(parser)
    args = parser.parse_args()

    soc = BaseSoC(toolchain=args.toolchain,
        sys_clk_freq = int(float(args.sys_clk_freq)),
        x5_clk_freq  = args.x5_clk_freq,
        **soc_core_argdict(args))
    builder = Builder(soc, **builder_argdict(args))
    builder.build(run=args.build)

    if args.load:
        prog = soc.platform.create_programmer()
        prog.load_bitstream(builder.get_bitstream_filename(mode="sram", ext=".svf")) # FIXME

if __name__ == "__main__":
    main()