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"""
This example runs a simple linux boot. It uses the 'riscv-disk-img' resource.
It is built with the sources in `src/riscv-fs` in [gem5 resources](
https://gem5.googlesource.com/public/gem5-resources).

Characteristics
---------------

* Runs exclusively on the RISC-V ISA with the classic caches
* Assumes that the kernel is compiled into the bootloader
* Automatically generates the DTB file
* Will boot but requires a user to login using `m5term` (username: `root`,
  password: `root`)
"""

import m5
from m5.objects import Root

from gem5.components.boards.riscv_board import RiscvBoard
from gem5.components.memory import SingleChannelDDR3_1600
from gem5.components.processors.simple_processor import SimpleProcessor
from gem5.components.cachehierarchies.classic.\
    private_l1_private_l2_cache_hierarchy import (
        PrivateL1PrivateL2CacheHierarchy,
    )
from gem5.components.processors.cpu_types import CPUTypes
from gem5.isas import ISA
from gem5.utils.requires import requires
from gem5.resources.resource import Resource

# Run a check to ensure the right version of gem5 is being used.
requires(isa_required=ISA.RISCV)

# Setup the cache hierarchy.
# For classic, PrivateL1PrivateL2 and NoCache have been tested.
# For Ruby, MESI_Two_Level and MI_example have been tested.
cache_hierarchy = PrivateL1PrivateL2CacheHierarchy(
    l1d_size="32KiB", l1i_size="32KiB", l2_size="512KiB"
)

# Setup the system memory.
memory = SingleChannelDDR3_1600()

# Setup a single core Processor.
processor = SimpleProcessor(cpu_type=CPUTypes.TIMING, num_cores=1)

# Setup the board.
board = RiscvBoard(
    clk_freq="1GHz",
    processor=processor,
    memory=memory,
    cache_hierarchy=cache_hierarchy,
)

# Set the Full System workload.
board.set_kernel_disk_workload(
                   kernel=Resource("riscv-bootloader-vmlinux-5.10"),
                   disk_image=Resource("riscv-disk-img"),
)

root = Root(full_system=True, system=board)

m5.instantiate()

print("Beginning simulation!")
# Note: This simulation will never stop. You can access the terminal upon boot
# using m5term (`./util/term`): `./m5term localhost <port>`. Note the `<port>`
# value is obtained from the gem5 terminal stdout. Look out for
# "system.platform.terminal: Listening for connections on port <port>".
exit_event = m5.simulate()