libnfc/libnfc/buses/uart.c

/*-
 * Public platform independent Near Field Communication (NFC) library
 * 
 * Copyright (C) 2009, 2010, Roel Verdult, Romuald Conty
 * 
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

/**
 * @file uart.c
 * @brief UART driver
 * 
 * This file contains 2 implementations of UART driver: first for POSIX systems, second for Windows system.
 */

/*
Based on RS232 code written by Teunis van Beelen available:
http://www.teuniz.net/RS-232/index.html
*/

#ifdef HAVE_CONFIG_H
  #include "config.h"
#endif // HAVE_CONFIG_H

#include "uart.h"

#include <nfc/nfc-messages.h>

// Test if we are dealing with unix operating systems
#ifndef _WIN32

#include <sys/select.h>
#include <termios.h>
typedef struct termios term_info;
typedef struct {
  int fd;           // Serial port file descriptor
  term_info tiOld;  // Terminal info before using the port
  term_info tiNew;  // Terminal info during the transaction
} serial_port_unix;

// timeval struct that define timeout delay for serial port
const struct timeval timeout = { 
  .tv_sec  =     0, // 0 second
  .tv_usec = 60000  // 60 ms
};

// Work-around to claim uart interface using the c_iflag (software input processing) from the termios struct
#define CCLAIMED 0x80000000

serial_port uart_open(const char* pcPortName)
{
  serial_port_unix* sp = malloc(sizeof(serial_port_unix));

  if (sp == 0) return INVALID_SERIAL_PORT;

  sp->fd = open(pcPortName, O_RDWR | O_NOCTTY | O_NONBLOCK);
  if(sp->fd == -1)
  {
    uart_close(sp);
    return INVALID_SERIAL_PORT;
  }

  if(tcgetattr(sp->fd,&sp->tiOld) == -1)
  {
    uart_close(sp);
    return INVALID_SERIAL_PORT;
  }

  // Make sure the port is not claimed already
  if (sp->tiOld.c_iflag & CCLAIMED)
  {
    uart_close(sp);
    return CLAIMED_SERIAL_PORT;
  }

  // Copy the old terminal info struct
  sp->tiNew = sp->tiOld;

  sp->tiNew.c_cflag = CS8 | CLOCAL | CREAD;
  sp->tiNew.c_iflag = CCLAIMED | IGNPAR;
  sp->tiNew.c_oflag = 0;
  sp->tiNew.c_lflag = 0;

  sp->tiNew.c_cc[VMIN] = 0;      // block until n bytes are received
  sp->tiNew.c_cc[VTIME] = 0;     // block until a timer expires (n * 100 mSec.)

  if(tcsetattr(sp->fd,TCSANOW,&sp->tiNew) == -1)
  {
    uart_close(sp);
    return INVALID_SERIAL_PORT;
  }

  tcflush(sp->fd, TCIFLUSH);
  return sp;
}

void uart_set_speed(serial_port sp, const uint32_t uiPortSpeed)
{
  DBG("Serial port speed requested to be set to %d bauds.", uiPortSpeed);
  // Set port speed (Input and Output)

  // Portability note: on some systems, B9600 != 9600 so we have to do
  // uint32_t <=> speed_t associations by hand.
  speed_t stPortSpeed = B9600;
  switch(uiPortSpeed) {
    case 9600: stPortSpeed = B9600;
    break;
    case 19200: stPortSpeed = B19200;
    break;
    case 38400: stPortSpeed = B38400;
    break;
#ifdef B57600
    case 57600: stPortSpeed = B57600;
    break;
#endif
#ifdef B115200
    case 115200: stPortSpeed = B115200;
    break;
#endif
#ifdef B230400
    case 230400: stPortSpeed = B230400;
    break;
#endif
#ifdef B460800
    case 460800: stPortSpeed = B460800;
    break;
#endif
    default:
      ERR("Unable to set serial port speed to %d bauds. Speed value must be one of those defined in termios(3).", uiPortSpeed);
  };
  const serial_port_unix* spu = (serial_port_unix*)sp;
  cfsetispeed((struct termios*)&spu->tiNew, stPortSpeed);
  cfsetospeed((struct termios*)&spu->tiNew, stPortSpeed);
  if( tcsetattr(spu->fd, TCSADRAIN, &spu->tiNew)  == -1)
  {
    ERR("%s", "Unable to apply new speed settings.");
  }
}

uint32_t uart_get_speed(const serial_port sp)
{
  uint32_t uiPortSpeed = 0;
  const serial_port_unix* spu = (serial_port_unix*)sp;
  switch (cfgetispeed(&spu->tiNew))
  {
    case B9600: uiPortSpeed = 9600;
    break;
    case B19200: uiPortSpeed = 19200;
    break;
    case B38400: uiPortSpeed = 38400;
    break;
#ifdef B57600
    case B57600: uiPortSpeed = 57600;
    break;
#endif
#ifdef B115200
    case B115200: uiPortSpeed = 115200;
    break;
#endif
#ifdef B230400
    case B230400: uiPortSpeed = 230400;
    break;
#endif
#ifdef B460800
    case B460800: uiPortSpeed = 460800;
    break;
#endif
  }

  return uiPortSpeed;
}

void uart_close(const serial_port sp)
{
  if (((serial_port_unix*)sp)->fd >= 0) {
    tcsetattr(((serial_port_unix*)sp)->fd,TCSANOW,&((serial_port_unix*)sp)->tiOld);
    close(((serial_port_unix*)sp)->fd);
  }
  free(sp);
}

bool uart_receive(const serial_port sp, byte_t* pbtRx, size_t* pszRxLen)
{
  int res;
  int byteCount;
  fd_set rfds;
  struct timeval tv;

  // Reset the output count  
  *pszRxLen = 0;

  do {
    // Reset file descriptor
    FD_ZERO(&rfds);
    FD_SET(((serial_port_unix*)sp)->fd,&rfds);
    tv = timeout;
    res = select(((serial_port_unix*)sp)->fd+1, &rfds, NULL, NULL, &tv);

    // Read error
    if (res < 0) {
      DBG("%s", "RX error.");
      return false;
    }

    // Read time-out
    if (res == 0) {
      if (*pszRxLen == 0) {
        // Error, we received no data
        DBG("%s", "RX time-out, buffer empty.");
        return false;
      } else {
        // We received some data, but nothing more is available
        return true;
      }
    }

    // Retrieve the count of the incoming bytes
    res = ioctl(((serial_port_unix*)sp)->fd, FIONREAD, &byteCount);
    if (res < 0) return false;

    // There is something available, read the data
    res = read(((serial_port_unix*)sp)->fd,pbtRx+(*pszRxLen),byteCount);

    // Stop if the OS has some troubles reading the data
    if (res <= 0) return false;

    *pszRxLen += res;

  } while (byteCount);

  return true;
}

bool uart_send(const serial_port sp, const byte_t* pbtTx, const size_t szTxLen)
{
  int32_t res;
  size_t szPos = 0;
  fd_set rfds;
  struct timeval tv;

  while (szPos < szTxLen)
  {
    // Reset file descriptor
    FD_ZERO(&rfds);
    FD_SET(((serial_port_unix*)sp)->fd,&rfds);
    tv = timeout;
    res = select(((serial_port_unix*)sp)->fd+1, NULL, &rfds, NULL, &tv);

    // Write error
    if (res < 0) {
      DBG("%s", "TX error.");
      return false;
    }

    // Write time-out
    if (res == 0) {
      DBG("%s", "TX time-out.");
      return false;
    }

    // Send away the bytes
    res = write(((serial_port_unix*)sp)->fd,pbtTx+szPos,szTxLen-szPos);
    
    // Stop if the OS has some troubles sending the data
    if (res <= 0) return false;

    szPos += res;
  }
  return true;
}

#else
// The windows serial port implementation

typedef struct { 
  HANDLE hPort;     // Serial port handle
  DCB dcb;          // Device control settings
  COMMTIMEOUTS ct;  // Serial port time-out configuration
} serial_port_windows;

serial_port uart_open(const char* pcPortName)
{
  char acPortName[255];
  serial_port_windows* sp = malloc(sizeof(serial_port_windows));

  // Copy the input "com?" to "\\.\COM?" format
  sprintf(acPortName,"\\\\.\\%s",pcPortName);
  _strupr(acPortName);

  // Try to open the serial port
  sp->hPort = CreateFileA(acPortName,GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
  if (sp->hPort == INVALID_HANDLE_VALUE)
  {
    uart_close(sp);
    return INVALID_SERIAL_PORT;
  }

  // Prepare the device control
  memset(&sp->dcb, 0, sizeof(DCB));
  sp->dcb.DCBlength = sizeof(DCB);
  if(!BuildCommDCBA("baud=9600 data=8 parity=N stop=1",&sp->dcb))
  {
    uart_close(sp);
    return INVALID_SERIAL_PORT;
  }

  // Update the active serial port
  if(!SetCommState(sp->hPort,&sp->dcb))
  {
    uart_close(sp);
    return INVALID_SERIAL_PORT;
  }

  sp->ct.ReadIntervalTimeout         = 0;
  sp->ct.ReadTotalTimeoutMultiplier  = 0;
  sp->ct.ReadTotalTimeoutConstant    = 30;
  sp->ct.WriteTotalTimeoutMultiplier = 0;
  sp->ct.WriteTotalTimeoutConstant   = 30;

  if(!SetCommTimeouts(sp->hPort,&sp->ct))
  {
    uart_close(sp);
    return INVALID_SERIAL_PORT;
  }

  PurgeComm(sp->hPort, PURGE_RXABORT | PURGE_RXCLEAR);

  return sp;
}

void uart_close(const serial_port sp)
{
  if (((serial_port_windows*)sp)->hPort != INVALID_HANDLE_VALUE) {
    CloseHandle(((serial_port_windows*)sp)->hPort);
  }
  free(sp);
}

void uart_set_speed(serial_port sp, const uint32_t uiPortSpeed)
{
  serial_port_windows* spw;

  DBG("Serial port speed requested to be set to %d bauds.", uiPortSpeed);
  // Set port speed (Input and Output)
  switch(uiPortSpeed) {
    case 9600:
    case 19200:
    case 38400:
    case 57600:
    case 115200:
    case 230400:
    case 460800:
    break;
    default:
      ERR("Unable to set serial port speed to %d bauds. Speed value must be one of these constants: 9600 (default), 19200, 38400, 57600, 115200, 230400 or 460800.", uiPortSpeed);
  };

  spw = (serial_port_windows*)sp;
  spw->dcb.BaudRate = uiPortSpeed;
  if (!SetCommState(spw->hPort, &spw->dcb))
  {
    ERR("Unable to apply new speed settings.");
  }
}

uint32_t uart_get_speed(const serial_port sp)
{
  const serial_port_windows* spw = (serial_port_windows*)sp;
  if (!GetCommState(spw->hPort, (serial_port)&spw->dcb))
    return spw->dcb.BaudRate;
  
  return 0;
}

bool uart_receive(const serial_port sp, byte_t* pbtRx, size_t* pszRxLen)
{
  ReadFile(((serial_port_windows*)sp)->hPort,pbtRx,*pszRxLen,(LPDWORD)pszRxLen,NULL);
  return (*pszRxLen != 0);
}

bool uart_send(const serial_port sp, const byte_t* pbtTx, const size_t szTxLen)
{
  DWORD dwTxLen = 0;
  return WriteFile(((serial_port_windows*)sp)->hPort,pbtTx,szTxLen,&dwTxLen,NULL);
  return (dwTxLen != 0);
}

#endif /* _WIN32 */