dtsc

#!/usr/bin/env python3

"""
    This script is part of BredOS-Tools, licenced under the GPL-3.0 licence.

    Bill Sideris <bill88t@bredos.org>
"""

import os
import sys
import argparse
import tempfile
import subprocess
import shutil


def preprocess_dts(input_file: str, temp_file: str, include: str, kernel: str) -> bool:
    """
    Preprocess the DTS file using the C preprocessor.
    """
    linux_include_path = kernel
    if not linux_include_path:
        linux_include_path = next(
            (
                os.path.join("/usr/src", d)
                for d in os.listdir("/usr/src")
                if "linux" in d and os.path.isdir(os.path.join("/usr/src", d))
            ),
            None,
        )
    if not linux_include_path:
        print(
            "Error: Could not find a valid Linux source include directory.",
            file=sys.stderr,
        )
        return False
    else:
        print("Using kernel: " + linux_include_path)

    cmd = [
        "cpp",
        "-nostdinc",
        "-I",
        os.path.join(linux_include_path, 'include'),
    ]

    if include is not None:
        cmd += ["-I", include]

    cmd += [
        "-undef",
        "-x",
        "assembler-with-cpp",
        input_file,
        temp_file,
    ]

    print("Preprocessing...")
    try:
        subprocess.run(cmd, check=True)
    except subprocess.CalledProcessError:
        print("Error: Preprocessing FAILED!", file=sys.stderr)
        return False
    return True


def compile_dts(temp_file: str, output_file: str, include: str = None) -> bool:
    """
    Compile the preprocessed DTS file into a DTBO or DTB.
    """
    cmd = ["dtc"]
    if include is not None:
        cmd += ["-i", include]
    cmd += ["-I", "dts", "-O", "dtb", temp_file, "-o", output_file]
    print("Compiling...")
    try:
        subprocess.run(cmd, check=True)
    except subprocess.CalledProcessError:
        print("Error: Compiling FAILED!", file=sys.stderr)
        return False
    return True


def check_dependencies() -> None:
    """
    Verify required tools are available on the system.
    """
    if shutil.which("dtc") is None:
        print(
            "Error: The 'dtc' command is not installed or not in PATH.", file=sys.stderr
        )
        sys.exit(1)


def main():
    parser = argparse.ArgumentParser(
        description="Compile a Device Tree Source (DTS) file into a Device Tree Blob (DTBO or DTB).",
        epilog="Example: ./compile_dts.py my_device_tree.dts -o output.dtbo",
    )
    parser.add_argument("input", nargs="?", help="Input DTS file")
    parser.add_argument(
        "-o",
        "--output",
        help="Output file (default: makes input_filename.dtb)",
        default=None,
    )
    parser.add_argument(
        "-i",
        "--include",
        help="Source of additional device tree files (optional)",
        default=None,
    )

    parser.add_argument(
        "-k",
        "--kernel",
        help="Manualy specify a kernel source path (default: autodetect)",
        default=None,
    )

    args = parser.parse_args()

    # Print help and exit if no arguments are provided
    if not args.input:
        parser.print_help()
        sys.exit(1)

    # Verify required tools
    check_dependencies()

    input_file = args.input
    output_file = args.output or input_file.rsplit(".", 1)[0] + ".dtb"
    include = args.include
    kernel = args.kernel

    if not os.path.isfile(input_file):
        print(f"Error: Input file '{input_file}' does not exist.", file=sys.stderr)
        sys.exit(1)

    if not (input_file.endswith(".dts") or input_file.endswith(".dtsi")):
        print("Error: Input file must be a device tree source file.", file=sys.stderr)
        sys.exit(1)

    with tempfile.NamedTemporaryFile(delete=False) as temp:
        temp_file = temp.name

    try:
        if not preprocess_dts(input_file, temp_file, include, kernel):
            sys.exit(1)
        if not compile_dts(temp_file, output_file, include):
            sys.exit(1)
    finally:
        if os.path.exists(temp_file):
            os.remove(temp_file)

    print(f"DTBO successfully created: {output_file}")


if __name__ == "__main__":
    main()