ostd 0.8.4

Rust OS framework that facilitates the development of and innovation in OS kernels
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

// SPDX-License-Identifier: MPL-2.0

//! I/O port access.

use core::marker::PhantomData;

pub struct WriteOnlyAccess;
pub struct ReadWriteAccess;

pub trait IoPortWriteAccess {}
pub trait IoPortReadAccess {}

impl IoPortWriteAccess for WriteOnlyAccess {}
impl IoPortWriteAccess for ReadWriteAccess {}
impl IoPortReadAccess for ReadWriteAccess {}

pub trait PortRead: Sized {
    unsafe fn read_from_port(_port: u16) -> Self {
        unimplemented!()
    }
}

pub trait PortWrite: Sized {
    unsafe fn write_to_port(_port: u16, _value: Self) {
        unimplemented!()
    }
}

impl PortRead for u8 {}
impl PortWrite for u8 {}
impl PortRead for u16 {}
impl PortWrite for u16 {}
impl PortRead for u32 {}
impl PortWrite for u32 {}

/// An I/O port, representing a specific address in the I/O address of x86.
///
/// The following code shows and example to read and write u32 value to an I/O port:
///
/// ```rust
/// static PORT: IoPort<u32, ReadWriteAccess> = unsafe { IoPort::new(0x12) };
///
/// fn port_value_increase(){
///     PORT.write(PORT.read() + 1)
/// }
/// ```
///
pub struct IoPort<T, A> {
    port: u16,
    value_marker: PhantomData<T>,
    access_marker: PhantomData<A>,
}

impl<T, A> IoPort<T, A> {
    /// Create an I/O port.
    ///
    /// # Safety
    ///
    /// This function is marked unsafe as creating an I/O port is considered
    /// a privileged operation.
    pub const unsafe fn new(port: u16) -> Self {
        Self {
            port,
            value_marker: PhantomData,
            access_marker: PhantomData,
        }
    }
}

impl<T: PortRead, A: IoPortReadAccess> IoPort<T, A> {
    /// Reads from the I/O port
    #[inline]
    pub fn read(&self) -> T {
        unsafe { PortRead::read_from_port(self.port) }
    }
}

impl<T: PortWrite, A: IoPortWriteAccess> IoPort<T, A> {
    /// Writes to the I/O port
    #[inline]
    pub fn write(&self, value: T) {
        unsafe { PortWrite::write_to_port(self.port, value) }
    }
}