cros_ec_python.ioports.devportio

  1"""
  2This file provides a way to interact with the `/dev/port` device file
  3as an alternative to the [portio](https://pypi.org/project/portio/) library.
  4
  5The speed is pretty much on par with the `portio` library, so there is no
  6real downside to using this method.
  7"""
  8
  9from typing import IO
 10
 11from .baseportio import PortIOClass
 12
 13
 14class DevPortIO(PortIOClass):
 15    """
 16    A class to interact with the `/dev/port` device file on Linux.
 17    """
 18
 19    _dev_port: IO | None = None
 20
 21    def __init__(self):
 22        """
 23        Initialize the `/dev/port` device file.
 24        """
 25        self._dev_port = open("/dev/port", "r+b", buffering=0)
 26
 27    def __del__(self):
 28        """
 29        Close the `/dev/port` device file.
 30        """
 31        if self._dev_port:
 32            self._dev_port.close()
 33
 34    def out_bytes(self, data: bytes, port: int) -> None:
 35        """
 36        Write data to the specified port.
 37        :param data: Data to write.
 38        :param port: Port to write to.
 39        """
 40        self._dev_port.seek(port)
 41        self._dev_port.write(data)
 42
 43    def outb(self, data: int, port: int) -> None:
 44        """
 45        Write a byte (8 bit) to the specified port.
 46        :param data: Byte to write.
 47        :param port: Port to write to.
 48        """
 49        self.out_bytes(data.to_bytes(1, "little"), port)
 50
 51    def outw(self, data: int, port: int) -> None:
 52        """
 53        Write a word (16 bit) to the specified port.
 54        :param data: Word to write.
 55        :param port: Port to write to.
 56        """
 57        self.out_bytes(data.to_bytes(2, "little"), port)
 58
 59    def outl(self, data: int, port: int) -> None:
 60        """
 61        Write a long (32 bit) to the specified port.
 62        :param data: Long to write.
 63        :param port: Port to write to.
 64        """
 65        self.out_bytes(data.to_bytes(4, "little"), port)
 66
 67    def in_bytes(self, port: int, num: int) -> bytes:
 68        """
 69        Read data from the specified port.
 70        :param port: Port to read from.
 71        :param num: Number of bytes to read.
 72        :return: Data read.
 73        """
 74        self._dev_port.seek(port)
 75        return self._dev_port.read(num)
 76
 77    def inb(self, port: int) -> int:
 78        """
 79        Read a byte (8 bit) from the specified port.
 80        :param port: Port to read from.
 81        :return: Byte read.
 82        """
 83        return int.from_bytes(self.in_bytes(port, 1), "little")
 84
 85    def inw(self, port: int) -> int:
 86        """
 87        Read a word (16 bit) from the specified port.
 88        :param port: Port to read from.
 89        :return: Word read.
 90        """
 91        return int.from_bytes(self.in_bytes(port, 2), "little")
 92
 93    def inl(self, port: int) -> int:
 94        """
 95        Read a long (32 bit) from the specified port.
 96        :param port: Port to read from.
 97        :return: Long read.
 98        """
 99        return int.from_bytes(self.in_bytes(port, 4), "little")
100
101    def ioperm(self, port: int, num: int, turn_on: bool) -> None:
102        """
103        `ioperm` stub function. It's not required for `/dev/port`.
104        """
105        pass
106
107    def iopl(self, level: int) -> None:
108        """
109        `iopl` stub function. It's not required for `/dev/port`.
110        """
111        pass