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direwolf/serial_port.c

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// TODO: Needs more clean up and testing of error conditions.
// TODO: use this in place of other similar code.
//
// This file is part of Dire Wolf, an amateur radio packet TNC.
//
// Copyright (C) 2014, 2015 John Langner, WB2OSZ
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 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 General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
//#define DEBUG 1
/*------------------------------------------------------------------
*
* Module: serial.c
*
* Purpose: Interface to serial port, hiding operating system differences.
*
*---------------------------------------------------------------*/
#include <stdio.h>
#if __WIN32__
#include <stdlib.h>
#include <windows.h>
#else
#define __USE_XOPEN2KXSI 1
#define __USE_XOPEN 1
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#endif
#include <assert.h>
#include <string.h>
#include "direwolf.h"
#include "textcolor.h"
#include "serial_port.h"
/*-------------------------------------------------------------------
*
* Name: serial_port_open
*
* Purpose: Open serial port.
*
* Inputs: devicename - For Windows, usually like COM5.
* For Linux, usually /dev/tty...
* "COMn" also allowed and converted to /dev/ttyS(n-1)
*
* baud - Speed. 4800, 9600, etc.
*
* Returns Handle for serial port or MYFDERROR for error.
*
*---------------------------------------------------------------*/
MYFDTYPE serial_port_open (char *devicename, int baud)
{
#if __WIN32__
MYFDTYPE fd;
DCB dcb;
int ok;
char bettername[50];
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("serial_port_open ( '%s', %d )\n", devicename, baud);
#endif
// Reference: http://www.robbayer.com/files/serial-win.pdf
// Need to use FILE_FLAG_OVERLAPPED for full duplex operation.
// Without it, write blocks when waiting on read.
// Read http://support.microsoft.com/kb/156932
// Bug fix in release 1.1 - Need to munge name for COM10 and up.
// http://support.microsoft.com/kb/115831
strcpy (bettername, devicename);
if (strncasecmp(devicename, "COM", 3) == 0) {
int n;
n = atoi(devicename+3);
if (n >= 10) {
strcpy (bettername, "\\\\.\\");
strcat (bettername, devicename);
}
}
fd = CreateFile(bettername, GENERIC_READ | GENERIC_WRITE,
0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
if (fd == MYFDERROR) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("ERROR - Could not open serial port %s.\n", devicename);
return (MYFDERROR);
}
/* Reference: http://msdn.microsoft.com/en-us/library/windows/desktop/aa363201(v=vs.85).aspx */
memset (&dcb, 0, sizeof(dcb));
dcb.DCBlength = sizeof(DCB);
ok = GetCommState (fd, &dcb);
if (! ok) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("serial_port_open: GetCommState failed.\n");
}
/* http://msdn.microsoft.com/en-us/library/windows/desktop/aa363214(v=vs.85).aspx */
dcb.DCBlength = sizeof(DCB);
switch (baud) {
case 1200: dcb.BaudRate = CBR_1200; break;
case 2400: dcb.BaudRate = CBR_2400; break;
case 4800: dcb.BaudRate = CBR_4800; break;
case 9600: dcb.BaudRate = CBR_9600; break;
case 19200: dcb.BaudRate = CBR_19200; break;
case 38400: dcb.BaudRate = CBR_38400; break;
case 57600: dcb.BaudRate = CBR_57600; break;
case 115200: dcb.BaudRate = CBR_115200; break;
default: text_color_set(DW_COLOR_ERROR);
dw_printf ("serial_port_open: Unsupported speed %d. Using 4800.\n", baud);
dcb.BaudRate = CBR_4800;
break;
}
dcb.fBinary = 1;
dcb.fParity = 0;
dcb.fOutxCtsFlow = 0;
dcb.fOutxDsrFlow = 0;
dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcb.fDsrSensitivity = 0;
dcb.fOutX = 0;
dcb.fInX = 0;
dcb.fErrorChar = 0;
dcb.fNull = 0; /* Don't drop nul characters! */
dcb.fRtsControl = 0;
dcb.ByteSize = 8;
dcb.Parity = NOPARITY;
dcb.StopBits = ONESTOPBIT;
ok = SetCommState (fd, &dcb);
if (! ok) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("serial_port_open: SetCommState failed.\n");
}
//text_color_set(DW_COLOR_INFO);
//dw_printf("Successful serial port open on %s.\n", devicename);
#else
/* Linux version. */
int fd;
struct termios ts;
int e;
char linuxname[50];
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("serial_port_open ( '%s' )\n", devicename);
#endif
/* Translate Windows device name into Linux name. */
/* COM1 -> /dev/ttyS0, etc. */
strcpy (linuxname, devicename);
if (strncasecmp(devicename, "COM", 3) == 0) {
int n = atoi (devicename + 3);
text_color_set(DW_COLOR_INFO);
dw_printf ("Converted serial port name '%s'", devicename);
if (n < 1) n = 1;
sprintf (linuxname, "/dev/ttyS%d", n-1);
dw_printf (" to Linux equivalent '%s'\n", linuxname);
}
fd = open (linuxname, O_RDWR);
if (fd == MYFDERROR) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("ERROR - Could not open serial port %s.\n", linuxname);
return (MYFDERROR);
}
e = tcgetattr (fd, &ts);
if (e != 0) { perror ("tcgetattr"); }
cfmakeraw (&ts);
ts.c_cc[VMIN] = 1; /* wait for at least one character */
ts.c_cc[VTIME] = 0; /* no fancy timing. */
switch (baud) {
case 1200: cfsetispeed (&ts, B1200); cfsetospeed (&ts, B1200); break;
case 2400: cfsetispeed (&ts, B2400); cfsetospeed (&ts, B2400); break;
case 4800: cfsetispeed (&ts, B4800); cfsetospeed (&ts, B4800); break;
case 9600: cfsetispeed (&ts, B9600); cfsetospeed (&ts, B9600); break;
case 19200: cfsetispeed (&ts, B19200); cfsetospeed (&ts, B19200); break;
case 38400: cfsetispeed (&ts, B38400); cfsetospeed (&ts, B38400); break;
case 57600: cfsetispeed (&ts, B57600); cfsetospeed (&ts, B57600); break;
case 115200: cfsetispeed (&ts, B115200); cfsetospeed (&ts, B115200); break;
default: text_color_set(DW_COLOR_ERROR);
dw_printf ("serial_port_open: Unsupported speed %d. Using 4800.\n", baud);
cfsetispeed (&ts, B4800); cfsetospeed (&ts, B4800);
break;
}
e = tcsetattr (fd, TCSANOW, &ts);
if (e != 0) { perror ("tcsetattr"); }
//text_color_set(DW_COLOR_INFO);
//dw_printf("Successfully opened serial port %s.\n", devicename);
#endif
return (fd);
}
/*-------------------------------------------------------------------
*
* Name: serial_port_write
*
* Purpose: Send characters to serial port.
*
* Inputs: fd - Handle from open.
* str - Pointer to array of bytes.
* len - Number of bytes to write.
*
* Returns Number of bytes written. Should be the same as len.
* -1 if error.
*
*---------------------------------------------------------------*/
int serial_port_write (MYFDTYPE fd, char *str, int len)
{
if (fd == MYFDERROR) {
return (-1);
}
#if __WIN32__
DWORD nwritten;
/* Without this, write blocks while we are waiting on a read. */
static OVERLAPPED ov_wr;
memset (&ov_wr, 0, sizeof(ov_wr));
if ( ! WriteFile (fd, str, len, &nwritten, &ov_wr))
{
int err = GetLastError();
if (err != ERROR_IO_PENDING)
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("Error writing to serial port. Error %d.\n\n", err);
}
}
else if (nwritten != len)
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("Error writing to serial port. Only %d of %d written.\n\n", (int)nwritten, len);
}
return (nwritten);
#else
int written;
written = write (fd, str, (size_t)len);
if (written != len)
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("Error writing to serial port. err=%d\n\n", written);
return (-1);
}
return (written);
#endif
} /* serial_port_write */
/*-------------------------------------------------------------------
*
* Name: serial_port_get1
*
* Purpose: Get one byte from the serial port. Wait if not ready.
*
* Inputs: fd - Handle from open.
*
* Returns: Value of byte in range of 0 to 255.
* -1 if error.
*
*--------------------------------------------------------------------*/
int serial_port_get1 (MYFDTYPE fd)
{
unsigned char ch;
#if __WIN32__ /* Native Windows version. */
DWORD n;
static OVERLAPPED ov_rd;
memset (&ov_rd, 0, sizeof(ov_rd));
ov_rd.hEvent = CreateEvent (NULL, TRUE, FALSE, NULL);
/* Overlapped I/O makes reading rather complicated. */
/* See: http://msdn.microsoft.com/en-us/library/ms810467.aspx */
/* It seems that the read completes OK with a count */
/* of 0 every time we send a message to the serial port. */
n = 0; /* Number of characters read. */
while (n == 0) {
if ( ! ReadFile (fd, &ch, 1, &n, &ov_rd))
{
int err1 = GetLastError();
if (err1 == ERROR_IO_PENDING)
{
/* Wait for completion. */
if (WaitForSingleObject (ov_rd.hEvent, INFINITE) == WAIT_OBJECT_0)
{
if ( ! GetOverlappedResult (fd, &ov_rd, &n, 1))
{
int err3 = GetLastError();
text_color_set(DW_COLOR_ERROR);
dw_printf ("Serial Port GetOverlappedResult error %d.\n\n", err3);
}
else
{
/* Success! n should be 1 */
}
}
}
else
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("Serial port read error %d.\n", err1);
return (-1);
}
}
} /* end while n==0 */
CloseHandle(ov_rd.hEvent);
if (n != 1) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Serial port failed to get one byte. n=%d.\n\n", (int)n);
}
#else /* Linux version */
int n;
n = read(fd, &ch, (size_t)1);
if (n != 1) {
text_color_set(DW_COLOR_DEBUG);
dw_printf ("serial_port_get1(%d) returns -1 for error.\n", fd);
return (-1);
}
#endif
#if DEBUGx
text_color_set(DW_COLOR_DEBUG);
if (isprint(ch)) {
dw_printf ("serial_port_get1(%d) returns 0x%02x = '%c'\n", fd, ch, ch);
}
else {
dw_printf ("serial_port_get1(%d) returns 0x%02x\n", fd, ch);
}
#endif
return (ch);
}
/*-------------------------------------------------------------------
*
* Name: serial_port_close
*
* Purpose: Close the device.
*
* Inputs: fd - Handle from open.
*
* Returns: None.
*
*--------------------------------------------------------------------*/
// TODO:
/* end serial_port.c */
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