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

//! Serial interface.

/// Serial error.
pub trait Error: core::fmt::Debug {
    /// Convert error to a generic serial error kind
    ///
    /// By using this method, serial errors freely defined by HAL implementations
    /// can be converted to a set of generic serial errors upon which generic
    /// code can act.
    fn kind(&self) -> ErrorKind;
}

impl Error for core::convert::Infallible {
    #[inline]
    fn kind(&self) -> ErrorKind {
        match *self {}
    }
}

/// Serial error kind.
///
/// This represents a common set of serial operation errors. HAL implementations are
/// free to define more specific or additional error types. However, by providing
/// a mapping to these common serial errors, generic code can still react to them.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
#[non_exhaustive]
pub enum ErrorKind {
    /// The peripheral receive buffer was overrun.
    Overrun,
    /// Received data does not conform to the peripheral configuration.
    /// Can be caused by a misconfigured device on either end of the serial line.
    FrameFormat,
    /// Parity check failed.
    Parity,
    /// Serial line is too noisy to read valid data.
    Noise,
    /// A different error occurred. The original error may contain more information.
    Other,
}

impl Error for ErrorKind {
    #[inline]
    fn kind(&self) -> ErrorKind {
        *self
    }
}

impl core::fmt::Display for ErrorKind {
    #[inline]
    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        match self {
            Self::Overrun => write!(f, "The peripheral receive buffer was overrun"),
            Self::Parity => write!(f, "Parity check failed"),
            Self::Noise => write!(f, "Serial line is too noisy to read valid data"),
            Self::FrameFormat => write!(
                f,
                "Received data does not conform to the peripheral configuration"
            ),
            Self::Other => write!(
                f,
                "A different error occurred. The original error may contain more information"
            ),
        }
    }
}

/// Serial error type trait.
///
/// This just defines the error type, to be used by the other traits.
pub trait ErrorType {
    /// Error type
    type Error: Error;
}

impl<T: ErrorType + ?Sized> ErrorType for &mut T {
    type Error = T::Error;
}

/// Read half of a serial interface.
///
/// Some serial interfaces support different data sizes (8 bits, 9 bits, etc.);
/// This can be encoded in this trait via the `Word` type parameter.
pub trait Read<Word: Copy = u8>: ErrorType {
    /// Reads a single word from the serial interface
    fn read(&mut self) -> nb::Result<Word, Self::Error>;
}

impl<T: Read<Word> + ?Sized, Word: Copy> Read<Word> for &mut T {
    #[inline]
    fn read(&mut self) -> nb::Result<Word, Self::Error> {
        T::read(self)
    }
}

/// Write half of a serial interface.
pub trait Write<Word: Copy = u8>: ErrorType {
    /// Writes a single word to the serial interface.
    fn write(&mut self, word: Word) -> nb::Result<(), Self::Error>;

    /// Ensures that none of the previously written words are still buffered.
    fn flush(&mut self) -> nb::Result<(), Self::Error>;
}

impl<T: Write<Word> + ?Sized, Word: Copy> Write<Word> for &mut T {
    #[inline]
    fn write(&mut self, word: Word) -> nb::Result<(), Self::Error> {
        T::write(self, word)
    }

    #[inline]
    fn flush(&mut self) -> nb::Result<(), Self::Error> {
        T::flush(self)
    }
}

/// Implementation of `core::fmt::Write` for the HAL's `serial::Write`.
///
/// TODO write example of usage

impl<Word, Error: self::Error> core::fmt::Write for dyn Write<Word, Error = Error> + '_
where
    Word: Copy + From<u8>,
{
    #[inline]
    fn write_str(&mut self, s: &str) -> core::fmt::Result {
        let _ = s
            .bytes()
            .map(|c| nb::block!(self.write(Word::from(c))))
            .last();
        Ok(())
    }
}