# Copyright (c) 2021 The Regents of the University of California
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import os
from typing import Optional

from ...utils.override import overrides
from .simple_board import SimpleBoard
from .abstract_board import AbstractBoard
from ..processors.abstract_processor import AbstractProcessor
from ..memory.abstract_memory_system import AbstractMemorySystem
from ..cachehierarchies.abstract_cache_hierarchy import AbstractCacheHierarchy
from ...isas import ISA
from ...runtime import get_runtime_isa

import m5
from m5.objects import (
    Bridge,
    PMAChecker,
    RiscvLinux,
    RiscvRTC,
    AddrRange,
    IOXBar,
    Clint,
    Plic,
    Uart8250,
    Terminal,
    LupioRTC,
    LupV,
    AddrRange,
    CowDiskImage,
    RawDiskImage,
    Frequency,
    RiscvMmioVirtIO,
    VirtIOBlock,
    Port,
)

from m5.util.fdthelper import (
    Fdt,
    FdtNode,
    FdtProperty,
    FdtPropertyStrings,
    FdtPropertyWords,
    FdtState,
)

class LupvBoard(SimpleBoard):
    """
    A board capable of full system simulation for RISC-V.
    This board uses a set of LupIO education-friendly devices.
    This board assumes that you will be booting Linux.

    **Limitations**
    * Only works with classic caches
    """

    def __init__(
        self,
        clk_freq: str,
        processor: AbstractProcessor,
        memory: AbstractMemorySystem,
        cache_hierarchy: AbstractCacheHierarchy,
    ) -> None:
        super().__init__(clk_freq, processor, memory, cache_hierarchy)
        if get_runtime_isa() != ISA.RISCV:
            raise EnvironmentError(
                "RiscvBoard will only work with the RISC-V ISA. Please"
                " recompile gem5 with ISA=RISCV."
            )
        if cache_hierarchy.is_ruby():
            raise EnvironmentError("RiscvBoard is not compatible with Ruby")
        self.workload = RiscvLinux()

        # Initialize all the devices that we want to use on this board
        # Interrupt IDS for PIC Device
        self._int_ids = { 'UART': 1, 'DISK': 2}

        # CLINT
        self.clint = Clint(pio_addr=0x2000000)

        # PLIC
        self.pic = Plic(pio_addr=0xc000000)

        #LupV Platform
        self.lupv = LupV(
            pic = self.pic,
            uart_int_id = self._int_ids['UART']
        )

        # LUPIO RTC
        self.lupio_rtc = LupioRTC(pio_addr=0x20004000)

        # VirtIO Disk
        self.disk = RiscvMmioVirtIO(
            vio=VirtIOBlock(),
            interrupt_id=self._int_ids['DISK'],
            pio_size=4096,
            pio_addr=0x10008000,
        )

        # UART
        self.uart = Uart8250(pio_addr=0x10000000)
        self.terminal = Terminal()

        pic_srcs = [
            self._int_ids['UART'],
            self._int_ids['DISK']
        ]
        self.pic.n_contexts = self.processor.get_num_cores() * 2
        self.pic.n_src = max(pic_srcs) + 1

        self.clint.num_threads = self.processor.get_num_cores()

        # Add the RTC
        # TODO: Why 100MHz? Does something else need to change when this does?
        self.rtc = RiscvRTC(frequency=Frequency("100MHz"))
        self.clint.int_pin = self.rtc.int_pin

        # Incoherent I/O bus
        self.iobus = IOXBar()

        self._on_chip_devices = [
            self.clint,
            self.pic,
        ]
        self._off_chip_devices = [
            self.uart,
            self.disk,
            self.lupio_rtc
        ]

    def _setup_io_devices(self) -> None:
        """Connect the I/O devices to the I/O bus"""
        for device in self._off_chip_devices:
            device.pio = self.iobus.mem_side_ports

        for device in self._on_chip_devices:
            device.pio = self.get_cache_hierarchy().get_mem_side_port()
        self.bridge = Bridge(delay="10ns")
        self.bridge.mem_side_port = self.iobus.cpu_side_ports
        self.bridge.cpu_side_port = (
            self.get_cache_hierarchy().get_mem_side_port()
        )
        self.bridge.ranges = [
            AddrRange(dev.pio_addr, size=dev.pio_size)
            for dev in self._off_chip_devices
        ]

    def _setup_pma(self) -> None:
        """Set the PMA devices on each core"""
        uncacheable_range = [
            AddrRange(dev.pio_addr, size=dev.pio_size)
            for dev in self._on_chip_devices + self._off_chip_devices
        ]
        # TODO: Not sure if this should be done per-core like in the example
        for cpu in self.get_processor().get_cores():
            cpu.get_mmu().pma_checker = PMAChecker(
                uncacheable=uncacheable_range
            )

    @overrides(AbstractBoard)
    def has_io_bus(self) -> bool:
        return True

    @overrides(AbstractBoard)
    def get_io_bus(self) -> IOXBar:
        return self.iobus

    def has_coherent_io(self) -> bool:
        return True

    def get_mem_side_coherent_io_port(self) -> Port:
        return self.iobus.mem_side_ports

    @overrides(AbstractBoard)
    def setup_memory_ranges(self):
        memory = self.get_memory()
        mem_size = memory.get_size()
        self.mem_ranges = [AddrRange(start=0x80000000, size=mem_size)]
        memory.set_memory_range(self.mem_ranges)

    def set_workload(
        self, bootloader: str, disk_image: str, command: Optional[str] = None
    ):
        """Setup the full system files
        See https://github.com/darchr/lupio-gem5/blob/lupio/README.md
        for running the full system, and downloading the right files to do so.
        The command passes in a boot loader and disk image, as well as the
        script to start the simulaiton.
        After the workload is set up, this function will generate the device
        tree file and output it to the output directory.
        **Limitations**
        * Only supports a Linux kernel
        * Must use the provided bootloader and disk image as denoted in the
        README above.
        """
        self.workload.object_file = bootloader
        # Set the disk image for the block device to use
        image = CowDiskImage(
            child=RawDiskImage(read_only=True),
            read_only=False
        )
        image.child.image_file = disk_image
        self.disk.vio.image = image

        # Linux boot command flags
        kernel_cmd = [
            "earlycon console=ttyS0",
            "root=/dev/vda1",
            "ro"
        ]
        self.workload.command_line = " ".join(kernel_cmd)

        # Note: This must be called after set_workload because it looks for an
        # attribute named "disk" and connects
        self._setup_io_devices()
        self._setup_pma()

        # Default DTB address if bbl is built with --with-dts option
        self.workload.dtb_addr = 0x87E00000

        # We need to wait to generate the device tree until after the disk is
        # set up. Now that the disk and workload are set, we can generate the
        # device tree file.
        self.generate_device_tree(m5.options.outdir)
        self.workload.dtb_filename = os.path.join(
            m5.options.outdir, "device.dtb"
        )

    def generate_device_tree(self, outdir: str) -> None:
        """Creates the dtb and dts files.
        Creates two files in the outdir: 'device.dtb' and 'device.dts'
        :param outdir: Directory to output the files
        """
        state = FdtState(addr_cells=2, size_cells=2, cpu_cells=1)
        root = FdtNode("/")
        root.append(state.addrCellsProperty())
        root.append(state.sizeCellsProperty())
        root.appendCompatible(["riscv-virtio"])
        for mem_range in self.mem_ranges:
            node = FdtNode("memory@%x" % int(mem_range.start))
            node.append(FdtPropertyStrings("device_type", ["memory"]))
            node.append(
                FdtPropertyWords(
                    "reg",
                    state.addrCells(mem_range.start)
                    + state.sizeCells(mem_range.size()),
                )
            )
            root.append(node)

        # See Documentation/devicetree/bindings/riscv/cpus.txt for details.
        cpus_node = FdtNode("cpus")
        cpus_state = FdtState(addr_cells=1, size_cells=0)
        cpus_node.append(cpus_state.addrCellsProperty())
        cpus_node.append(cpus_state.sizeCellsProperty())
        # Used by the CLINT driver to set the timer frequency. Value taken from
        # RISC-V kernel docs (Note: freedom-u540 is actually 1MHz)
        cpus_node.append(FdtPropertyWords("timebase-frequency", [100000000]))
        for i, core in enumerate(self.get_processor().get_cores()):
            node = FdtNode(f"cpu@{i}")
            node.append(FdtPropertyStrings("device_type", "cpu"))
            node.append(FdtPropertyWords("reg", state.CPUAddrCells(i)))
            node.append(FdtPropertyStrings("mmu-type", "riscv,sv48"))
            node.append(FdtPropertyStrings("status", "okay"))
            node.append(FdtPropertyStrings("riscv,isa", "rv64imafdc"))
            # TODO: Should probably get this from the core.
            freq = self.clk_domain.clock[0].frequency
            node.appendCompatible(["riscv"])
            int_phandle = state.phandle(f"cpu@{i}.int_state")
            int_node = FdtNode("interrupt-controller")
            int_state = FdtState(interrupt_cells=1)
            int_phandle = state.phandle(f"cpu@{i}.int_state")
            int_node.append(int_state.interruptCellsProperty())
            int_node.append(FdtProperty("interrupt-controller"))
            int_node.appendCompatible("riscv,cpu-intc")
            int_node.append(FdtPropertyWords("phandle", [int_phandle]))
            node.append(int_node)
            cpus_node.append(node)
        root.append(cpus_node)

        soc_node = FdtNode("soc")
        soc_state = FdtState(addr_cells=2, size_cells=2)
        soc_node.append(soc_state.addrCellsProperty())
        soc_node.append(soc_state.sizeCellsProperty())
        soc_node.append(FdtProperty("ranges"))
        soc_node.appendCompatible(["simple-bus"])

        # CLINT node
        clint = self.clint
        clint_node = clint.generateBasicPioDeviceNode(
            soc_state, "clint", clint.pio_addr, clint.pio_size
        )
        int_extended = list()
        for i, core in enumerate(self.get_processor().get_cores()):
            phandle = state.phandle(f"cpu@{i}.int_state")
            int_extended.append(phandle)
            int_extended.append(0x3)
            int_extended.append(phandle)
            int_extended.append(0x7)
        clint_node.append(
            FdtPropertyWords("interrupts-extended", int_extended)
        )
        clint_node.appendCompatible(["riscv,clint0"])
        soc_node.append(clint_node)

        # PLIC node
        plic = self.pic
        plic_node = plic.generateBasicPioDeviceNode(
            soc_state, "plic", plic.pio_addr, plic.pio_size
        )

        int_state = FdtState(addr_cells=0, interrupt_cells=1)
        plic_node.append(int_state.addrCellsProperty())
        plic_node.append(int_state.interruptCellsProperty())

        phandle = int_state.phandle(plic)
        plic_node.append(FdtPropertyWords("phandle", [phandle]))
        plic_node.append(FdtPropertyWords("riscv,ndev", [plic.n_src - 1]))

        int_extended = list()
        for i, core in enumerate(self.get_processor().get_cores()):
            phandle = state.phandle(f"cpu@{i}.int_state")
            int_extended.append(phandle)
            int_extended.append(0xB)
            int_extended.append(phandle)
            int_extended.append(0x9)

        plic_node.append(FdtPropertyWords("interrupts-extended", int_extended))
        plic_node.append(FdtProperty("interrupt-controller"))
        plic_node.appendCompatible(["riscv,plic0"])

        soc_node.append(plic_node)

        # UART node
        uart = self.uart
        uart_node = uart.generateBasicPioDeviceNode(
            soc_state, "uart", uart.pio_addr, uart.pio_size
        )
        uart_node.append(
            FdtPropertyWords("interrupts", [self._int_ids['UART']])
        )
        uart_node.append(FdtPropertyWords("clock-frequency", [0x384000]))
        uart_node.append(
            FdtPropertyWords("interrupt-parent", soc_state.phandle(plic))
        )
        uart_node.appendCompatible(["ns8250"])
        soc_node.append(uart_node)

        # VirtIO MMIO disk node
        disk = self.disk
        disk_node = disk.generateBasicPioDeviceNode(
            soc_state, "virtio_mmio", disk.pio_addr, disk.pio_size
        )
        disk_node.append(FdtPropertyWords("interrupts", [disk.interrupt_id]))
        disk_node.append(
            FdtPropertyWords("interrupt-parent", soc_state.phandle(plic))
        )
        disk_node.appendCompatible(["virtio,mmio"])
        soc_node.append(disk_node)

        # LupioRTC Device
        lupio_rtc = self.lupio_rtc
        lupio_rtc_node = lupio_rtc.generateBasicPioDeviceNode(
            soc_state, "lupio-rtc", lupio_rtc.pio_addr, lupio_rtc.pio_size
        )
        lupio_rtc_node.appendCompatible(["lupio,rtc"])
        soc_node.append(lupio_rtc_node)

        root.append(soc_node)
        fdt = Fdt()
        fdt.add_rootnode(root)
        fdt.writeDtsFile(os.path.join(outdir, "device.dts"))
        fdt.writeDtbFile(os.path.join(outdir, "device.dtb"))