1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

//! Access to I/O ports

use core::marker::PhantomData;

pub use crate::structures::port::{PortRead, PortReadWrite, PortWrite};

impl PortRead for u8 {
    #[inline]
    unsafe fn read_from_port(port: u16) -> u8 {
        let value: u8;
        asm!("inb $1, $0" : "={al}"(value) : "N{dx}"(port) :: "volatile");
        value
    }
}

impl PortRead for u16 {
    #[inline]
    unsafe fn read_from_port(port: u16) -> u16 {
        let value: u16;
        asm!("inw $1, $0" : "={ax}"(value) : "N{dx}"(port) :: "volatile");
        value
    }
}

impl PortRead for u32 {
    #[inline]
    unsafe fn read_from_port(port: u16) -> u32 {
        let value: u32;
        asm!("inl $1, $0" : "={eax}"(value) : "N{dx}"(port) :: "volatile");
        value
    }
}

impl PortWrite for u8 {
    #[inline]
    unsafe fn write_to_port(port: u16, value: u8) {
        asm!("outb $1, $0" :: "N{dx}"(port), "{al}"(value) :: "volatile");
    }
}

impl PortWrite for u16 {
    #[inline]
    unsafe fn write_to_port(port: u16, value: u16) {
        asm!("outw $1, $0" :: "N{dx}"(port), "{ax}"(value) :: "volatile");
    }
}

impl PortWrite for u32 {
    #[inline]
    unsafe fn write_to_port(port: u16, value: u32) {
        asm!("outl $1, $0" :: "N{dx}"(port), "{eax}"(value) :: "volatile");
    }
}

impl PortReadWrite for u8 {}
impl PortReadWrite for u16 {}
impl PortReadWrite for u32 {}

/// A read only I/O port.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PortReadOnly<T: PortRead> {
    port: u16,
    phantom: PhantomData<T>,
}

/// A write only I/O port.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct PortWriteOnly<T: PortWrite> {
    port: u16,
    phantom: PhantomData<T>,
}

/// An I/O port.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Port<T: PortReadWrite> {
    port: u16,
    phantom: PhantomData<T>,
}

impl<T: PortRead> PortReadOnly<T> {
    /// Creates a read only I/O port with the given port number.
    pub const fn new(port: u16) -> PortReadOnly<T> {
        PortReadOnly {
            port: port,
            phantom: PhantomData,
        }
    }

    /// Reads from the port.
    ///
    /// This function is unsafe because the I/O port could have side effects that violate memory
    /// safety.
    #[inline]
    pub unsafe fn read(&mut self) -> T {
        T::read_from_port(self.port)
    }
}

impl<T: PortWrite> PortWriteOnly<T> {
    /// Creates a write only I/O port with the given port number.
    pub const fn new(port: u16) -> PortWriteOnly<T> {
        PortWriteOnly {
            port: port,
            phantom: PhantomData,
        }
    }

    /// Writes to the port.
    ///
    /// This function is unsafe because the I/O port could have side effects that violate memory
    /// safety.
    #[inline]
    pub unsafe fn write(&mut self, value: T) {
        T::write_to_port(self.port, value)
    }
}

impl<T: PortReadWrite> Port<T> {
    /// Creates an I/O port with the given port number.
    pub const fn new(port: u16) -> Port<T> {
        Port {
            port: port,
            phantom: PhantomData,
        }
    }

    /// Reads from the port.
    ///
    /// This function is unsafe because the I/O port could have side effects that violate memory
    /// safety.
    #[inline]
    pub unsafe fn read(&mut self) -> T {
        T::read_from_port(self.port)
    }

    /// Writes to the port.
    ///
    /// This function is unsafe because the I/O port could have side effects that violate memory
    /// safety.
    #[inline]
    pub unsafe fn write(&mut self, value: T) {
        T::write_to_port(self.port, value)
    }
}