lin_bus/
master.rs

1//! LIN bus master implementation
2use crate::driver;
3use crate::frame::Frame;
4use crate::PID;
5use crate::{checksum, classic_checksum};
6
7pub trait Master {
8    type Error;
9    fn send_wakeup(&mut self) -> Result<(), Self::Error>;
10    fn write_frame(&mut self, frame: &Frame) -> Result<(), Self::Error>;
11    fn read_frame(&mut self, pid: PID, data_lengh: usize) -> Result<Frame, Self::Error>;
12}
13
14impl<Driver> Master for Driver
15where
16    Driver: driver::Master,
17{
18    type Error = Driver::Error;
19
20    fn send_wakeup(&mut self) -> Result<(), Driver::Error> {
21        Driver::send_wakeup(self)
22    }
23
24    fn write_frame(&mut self, frame: &Frame) -> Result<(), Driver::Error> {
25        self.send_header(frame.get_pid())?;
26        self.write(frame.get_data_with_checksum())
27    }
28
29    fn read_frame(&mut self, pid: PID, data_length: usize) -> Result<Frame, Driver::Error> {
30        assert!(data_length <= 8, "Maximum data length is 8 bytes");
31        self.send_header(pid)?;
32        let mut frame = Frame {
33            pid,
34            data_length,
35            buffer: [0u8; 9],
36        };
37        self.read(&mut frame.buffer[0..=data_length])?;
38
39        let checksum = {
40            if pid.uses_classic_checksum() {
41                classic_checksum(&frame.buffer[0..data_length])
42            } else {
43                checksum(pid, &frame.buffer[0..data_length])
44            }
45        };
46        if checksum != frame.buffer[data_length] {
47            Err(Driver::Error::from(driver::Error::Checksum))
48        } else {
49            Ok(frame)
50        }
51    }
52}
53
54#[cfg(test)]
55mod tests {
56    use super::*;
57
58    struct FrameTestData<'a> {
59        pid: PID,
60        data: &'a [u8],
61        frame: Frame,
62    }
63    #[test]
64    fn test_frame_from_data() {
65        let test_data = [FrameTestData {
66            pid: PID::new(0xDD),
67            data: &[0x01],
68            frame: Frame {
69                pid: PID::new(0xDD),
70                buffer: [0x01, 0x21, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00],
71                data_length: 1,
72            },
73        }];
74        for d in &test_data {
75            let frame = Frame::from_data(d.pid, d.data);
76            assert_eq!(frame, d.frame);
77            assert_eq!(frame.get_data(), d.data);
78            assert_eq!(frame.get_pid(), d.pid);
79            assert_eq!(frame.get_data_with_checksum().len(), d.data.len() + 1);
80        }
81    }
82
83    #[test]
84    fn test_data_decode() {
85        let test_data = [
86            (
87                Frame::from_data(PID::new(80), &[254, 251, 239, 255]),
88                [1022, 1022, 2046],
89            ),
90            (
91                Frame::from_data(PID::new(80), &[3, 12, 240, 182]),
92                [3, 3, 879],
93            ),
94            (
95                Frame::from_data(PID::new(80), &[3, 12, 0, 183]),
96                [3, 3, 880],
97            ),
98            (
99                Frame::from_data(PID::new(80), &[2, 12, 240, 182]),
100                [2, 3, 879],
101            ),
102            (Frame::from_data(PID::new(80), &[2, 8, 0, 183]), [2, 2, 880]),
103        ];
104
105        for d in &test_data {
106            assert_eq!(d.0.decode::<u16>(0, 10), d.1[0]);
107            assert_eq!(d.0.decode::<u16>(10, 10), d.1[1]);
108            assert_eq!(d.0.decode::<u16>(20, 11), d.1[2]);
109        }
110    }
111
112    #[test]
113    fn test_data_decode_all_bits() {
114        let frame = Frame::from_data(PID::new(80), &[0x55, 0xDD]);
115        assert_eq!(frame.decode::<u16>(0, 16), 0xdd55);
116    }
117}
lin_bus/master.rs

lin_bus/
master.rs
