cros_ec_python.ioports.freebsdportio

  1"""
  2This file provides a way to interact with the `/dev/io` device file on
  3FreeBSD.
  4"""
  5
  6from typing import Final, IO
  7from fcntl import ioctl
  8import struct
  9
 10from .baseportio import PortIOClass
 11
 12IODEV_PIO_READ: Final = 0
 13IODEV_PIO_WRITE: Final = 1
 14
 15
 16def _IOC(inout: int, group: str, num: int, length: int):
 17    """
 18    Create an ioctl command number.
 19    Based on the FreeBSD kernels sys/sys/ioccom.h.
 20    """
 21    IOCPARM_SHIFT: Final = 13  # number of bits for ioctl size
 22    IOCPARM_MASK: Final = ((1 << IOCPARM_SHIFT) - 1)  # parameter length mask
 23
 24    return (((inout) | (((length) & IOCPARM_MASK) << 16) | (ord(group) << 8) | (num)))
 25
 26
 27def _IOWR(group: str, num: int, length: int):
 28    """
 29    Create an ioctl command number for read/write commands.
 30    Based on the FreeBSD kernels sys/sys/ioccom.h.
 31    """
 32    IOC_VOID: Final = 0x20000000  # no parameters
 33    IOC_OUT: Final = 0x40000000  # copy out parameters
 34    IOC_IN: Final = 0x80000000  # copy in parameters
 35    IOC_INOUT: Final = (IOC_IN|IOC_OUT)  # copy parameters in and out
 36    IOC_DIRMASK: Final = (IOC_VOID|IOC_OUT|IOC_IN)  # mask for IN/OUT/VOID
 37    return _IOC(IOC_INOUT, group, num, length)
 38
 39
 40def IODEV_PIO():
 41    """
 42    Create an ioctl command number for the `/dev/io` device file.
 43    """
 44
 45    # struct iodev_pio_req {
 46    # 	u_int access;
 47    # 	u_int port;
 48    # 	u_int width;
 49    # 	u_int val;
 50    # };
 51
 52    length = struct.calcsize("IIII")
 53    return _IOWR("I", 0, length)
 54
 55
 56class FreeBsdPortIO(PortIOClass):
 57    """
 58    A class to interact with the `/dev/io` device file on FreeBSD.
 59    """
 60
 61    _dev_io: IO | None = None
 62
 63    def __init__(self):
 64        """
 65        Initialize the `/dev/port` device file.
 66        """
 67        self._dev_io = open("/dev/io", "wb", buffering=0)
 68
 69    def __del__(self):
 70        """
 71        Close the `/dev/port` device file.
 72        """
 73        if self._dev_io:
 74            self._dev_io.close()
 75
 76    def out_bytes(self, data: bytes, port: int) -> None:
 77        """
 78        Write data to the specified port.
 79        :param data: Data to write.
 80        :param port: Port to write to.
 81        """
 82        iodev_pio_req = struct.pack(
 83            "IIII", IODEV_PIO_WRITE, port, len(data), int.from_bytes(data, "little")
 84        )
 85        ioctl(self._dev_io, IODEV_PIO(), iodev_pio_req)
 86
 87    def outb(self, data: int, port: int) -> None:
 88        """
 89        Write a byte (8 bit) to the specified port.
 90        :param data: Byte to write.
 91        :param port: Port to write to.
 92        """
 93        self.out_bytes(data.to_bytes(1, "little"), port)
 94
 95    def outw(self, data: int, port: int) -> None:
 96        """
 97        Write a word (16 bit) to the specified port.
 98        :param data: Word to write.
 99        :param port: Port to write to.
100        """
101        self.out_bytes(data.to_bytes(2, "little"), port)
102
103    def outl(self, data: int, port: int) -> None:
104        """
105        Write a long (32 bit) to the specified port.
106        :param data: Long to write.
107        :param port: Port to write to.
108        """
109        self.out_bytes(data.to_bytes(4, "little"), port)
110
111    def in_bytes(self, port: int, num: int) -> bytes:
112        """
113        Read data from the specified port.
114        :param port: Port to read from.
115        :param num: Number of bytes to read (1 - 4).
116        :return: Data read.
117        """
118        iodev_pio_req = struct.pack("IIII", IODEV_PIO_READ, port, num, 0)
119        return ioctl(self._dev_io, IODEV_PIO(), iodev_pio_req)[struct.calcsize("III") :]
120
121    def inb(self, port: int) -> int:
122        """
123        Read a byte (8 bit) from the specified port.
124        :param port: Port to read from.
125        :return: Byte read.
126        """
127        return int.from_bytes(self.in_bytes(port, 1), "little")
128
129    def inw(self, port: int) -> int:
130        """
131        Read a word (16 bit) from the specified port.
132        :param port: Port to read from.
133        :return: Word read.
134        """
135        return int.from_bytes(self.in_bytes(port, 2), "little")
136
137    def inl(self, port: int) -> int:
138        """
139        Read a long (32 bit) from the specified port.
140        :param port: Port to read from.
141        :return: Long read.
142        """
143        return int.from_bytes(self.in_bytes(port, 4), "little")
144
145    def ioperm(self, port: int, num: int, turn_on: bool) -> None:
146        """
147        `ioperm` stub function. The iopl will already be raised from opening `/dev/io` and is not required.
148        """
149        pass
150
151    def iopl(self, level: int) -> None:
152        """
153        `iopl` stub function. The iopl will already be raised from opening `/dev/io` and is not required.
154        """
155        pass