dmrconfig/src/serial.rs

use std::ffi::{CStr};
use libc::{c_char, c_int, c_uchar, c_void};
use std::process::exit;
use std::time::Duration;

//hack to handle the serial device path state
pub static mut device_path: Option<String> = None;

extern {
  fn find_path(vid: libc::c_int, pid: libc::c_int) -> *const c_char;
  fn serial_identify(s: *const c_char) -> *const c_char;
  fn serial_close();
}

/// Connect to the specified device.
/// Initiate the programming session.
pub fn serial_init(vid: u32, pid: u32, trace_flag: bool) -> Option<String> {
    let dev_path = unsafe { find_path(vid as i32, pid as i32) };

    if dev_path.is_null() {
      if trace_flag {
        eprintln!("Cannot find USB device: {:#x}{:#x}", vid, pid);
      }
      return None;
    }

    let dev_path = unsafe { CStr::from_ptr(dev_path).to_str().unwrap().to_string() };
    println!("Serial port: {}", dev_path);
    Some(dev_path)
}

fn send_receive(port: &mut dyn serial::SerialPort, command: &[u8], reply_len: usize, trace: bool) -> Vec<u8> {
  if trace {
    eprintln!("----Send [{}] {:?}", command.len(), command);
  }

  match port.write(&command) {
    Ok(n) => {
      if trace {
        eprintln!("Wrote {} bytes over serial", n);
      }
    },
    Err(e) => {
      eprintln!("Serial write error: {}", e);
      exit(-1);
    }
  };

  let mut buf: Vec<u8> = vec![0; reply_len];
  match port.read(&mut buf) {
    Ok(n) if n == reply_len => {
      if trace {
        eprintln!("----Received [{}] {:?}", reply_len, buf);
      }
    },
    Ok(n) => {
      eprintln!("Serial: read {} bytes, expected {}", n, reply_len);
    }
    Err(e) => {
      eprintln!("Serial read error: {}", e);
      exit(-1);
    }
  };
  buf
}

#[no_mangle]
pub extern "C" fn serial_read_region(addr: c_int, data: *mut c_uchar, nbytes: c_int) {
  use serial::prelude::*;

  let dev_path = unsafe {
    match device_path {
      Some(ref s) => s.clone(),
      None => {
        eprintln!("No serial device path set, exiting");
        exit(-1);
      }
    }
  };

  let mut port = match serial::open(&dev_path) {
    Ok(port) => port,
    Err(err) => {
      println!("{}", err);
      exit(-1);
    }
  };

  port.reconfigure(&|settings: &mut dyn SerialPortSettings| {
    settings.set_baud_rate(serial::BaudRate::Baud115200)?;
    settings.set_char_size(serial::CharSize::Bits8);
    Ok(())
  }).unwrap();
  port.set_timeout(Duration::new(1,0)).unwrap();

  const DATA_SIZE: usize = 64;
  let num_bytes = nbytes as usize;
  let addr = addr as usize;

  let mut output_data = vec![];

  let mut n = 0;
  while n < num_bytes {
    // Serial read command: 'R' aa aa aa aa 0x10
    let cmd: [u8; 6] = [
      0x52, // ASCII 'R'
      ((addr + n) >> 24) as u8,
      ((addr + n) >> 16) as u8,
      ((addr + n) >> 8) as u8,
      (addr + n) as u8,
      64,
    ];
    let reply_len = 8 + DATA_SIZE;
    eprintln!("Here in serial_read_region");
    let reply = send_receive(&mut port, &cmd, reply_len, true);
    if reply[0] != b'W' || reply[7+DATA_SIZE] != 0x6 {
      eprintln!("serial_read_region: wrong read reply: {:?} shit: {}", reply, reply[7+DATA_SIZE]);
      exit(-1);
    }

    //Compute checksum
    let mut checksum: u8 = reply[1];
    for idx in 2..6+DATA_SIZE {
      checksum = checksum.overflowing_add(reply[idx]).0;
    }
    let expected_checksum = reply[6+DATA_SIZE];
    if checksum != expected_checksum {
        eprintln!("serial_read_region: wrong read checksum {}, expected {}", checksum, expected_checksum);
        exit(-1);
    }

    output_data.extend(reply.into_iter());
    n += DATA_SIZE;
  }

  let n = output_data.len();
  let ptr = output_data.as_ptr() as *const c_void;
  unsafe {
    libc::memcpy(data as *mut c_void, ptr, n);
  }
}

#[no_mangle]
pub extern "C" fn serial_write_region(addr: c_int, data: *mut c_uchar, nbytes: c_int) {
  use serial::prelude::*;

  let dev_path = unsafe {
    match device_path {
      Some(ref s) => s.clone(),
      None => {
        eprintln!("No serial device path set, exiting");
        exit(-1);
      }
    }
  };

  let mut port = match serial::open(&dev_path) {
    Ok(port) => port,
    Err(err) => {
      println!("{}", err);
      exit(-1);
    }
  };

  port.reconfigure(&|settings: &mut dyn SerialPortSettings| {
    settings.set_baud_rate(serial::BaudRate::Baud115200)?;
    settings.set_char_size(serial::CharSize::Bits8);
    Ok(())
  }).unwrap();
  port.set_timeout(Duration::new(1,0)).unwrap();

  const DATA_SIZE: usize = 16;

  let num_bytes = nbytes as usize;
  let addr = addr as usize;

  let mut n = 0;
  while n < num_bytes {
    let mut cmd: [u8; 8 + DATA_SIZE] = [0; 8 + DATA_SIZE];
    cmd[0] = 0x57; // ASCII 'W'
    cmd[1] = ((addr + n) >> 24) as u8;
    cmd[2] = ((addr + n) >> 16) as u8;
    cmd[3] = ((addr + n) >> 8) as u8;
    cmd[4] = (addr + n) as u8;
    cmd[5] = DATA_SIZE as u8;

    let ptr = unsafe {
      cmd.as_mut_ptr().offset(6) as *mut c_void
    };
    unsafe {
      libc::memcpy(ptr, data.offset(n as isize) as *const c_void, DATA_SIZE);
    }

    //Compute checksum
    let mut checksum: u8 = cmd[1];
    for idx in 2..(6+DATA_SIZE) {
      checksum = checksum.overflowing_add(cmd[idx]).0;
    }
    cmd[DATA_SIZE+6] = checksum;
    cmd[DATA_SIZE+7] = b'\x06'; // CMD_ACK byte
    let reply = send_receive(&mut port, &cmd, 1, true);
    if reply[0] != b'\x06' {
      eprintln!("serial_write_region: wrong acknowledge {:?}, expected: {:?}", reply, b'\x06');
      exit(-1);
    }

    n += DATA_SIZE as usize;
  }
}


/// Query and return the device identification string.
/// On error, return None.
pub fn identify(dev_path: &str) -> Option<String> {
  use serial::prelude::*;

  let mut port = match serial::open(dev_path) {
    Ok(port) => port,
    Err(err) => {
      println!("{}", err);
      exit(-1);
    }
  };

  port.reconfigure(&|settings: &mut dyn SerialPortSettings| {
    settings.set_baud_rate(serial::BaudRate::Baud115200)?;
    settings.set_char_size(serial::CharSize::Bits8);
    Ok(())
  }).unwrap();
  port.set_timeout(Duration::new(1,0)).unwrap();

  let program_cmd = b"PROGRAM";
  let program_cmd_2 = b"\x02";

  let program_ack = b"QX\x06";
  let command_ack: u8 = b'\x06';

  let output = send_receive(&mut port, program_cmd, 3, true);
  if output != program_ack {
    eprintln!("serial identify: wrong PRG acknowledge {:?}, expected {:?}", output, program_ack);
  }

  // Expected output should be something like:
  // 49 44 38 36 38 55 56 45 00 56 31 30 32 00 00 06
  //  I  D  8  6  8  U  V  E     V  1  0  2
  let output = send_receive(&mut port, program_cmd_2, 16, true);
  if (output[0] != 'I' as u8) || (output[15] != command_ack) {
    eprintln!("serial identify: wrong PRG2 reply {:?} expected 'I'...'\\6'", output);
  }

  return Some(String::from_utf8(output[1..7].to_vec()).unwrap())
}

/// Close the serial port.
pub fn close() {
  unsafe {
    serial_close();
  }
}