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bacnet_stack/bacnet-stack/ports/linux/rs485.c
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/*####COPYRIGHTBEGIN####
-------------------------------------------
Copyright (C) 2007 Steve Karg <skarg@users.sourceforge.net>
Updated by ?????? ????? 2011 <nikola.jelic@euroicc.com>
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, write to:
The Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307
USA.
As a special exception, if other files instantiate templates or
use macros or inline functions from this file, or you compile
this file and link it with other works to produce a work based
on this file, this file does not by itself cause the resulting
work to be covered by the GNU General Public License. However
the source code for this file must still be made available in
accordance with section (3) of the GNU General Public License.
This exception does not invalidate any other reasons why a work
based on this file might be covered by the GNU General Public
License.
-------------------------------------------
####COPYRIGHTEND####*/
/** @file linux/rs485.c Provides Linux-specific functions for RS-485 serial. */
/* The module handles sending data out the RS-485 port */
/* and handles receiving data from the RS-485 port. */
/* Customize this file for your specific hardware */
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Linux includes */
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>
#include <sched.h>
/* Local includes */
#include "mstp.h"
#include "rs485.h"
#include "fifo.h"
#include <pthread.h>
#include <sys/select.h>
#include <sys/time.h>
/* Posix serial programming reference:
http://www.easysw.com/~mike/serial/serial.html */
/* Use ionice wrapper to improve serial performance:
$ sudo ionice -c 1 -n 0 ./bin/bacserv 12345
*/
/* handle returned from open() */
static int RS485_Handle = -1;
/* baudrate settings are defined in <asm/termbits.h>, which is
included by <termios.h> */
static unsigned int RS485_Baud = B38400;
/* serial port name, /dev/ttyS0,
/dev/ttyUSB0 for USB->RS485 from B&B Electronics USOPTL4 */
static char *RS485_Port_Name = "/dev/ttyUSB0";
/* some terminal I/O have RS-485 specific functionality */
#ifndef RS485MOD
#define RS485MOD 0
#endif
/* serial I/O settings */
static struct termios RS485_oldtio;
/* Ring buffer for incoming bytes, in order to speed up the receiving. */
static FIFO_BUFFER Rx_FIFO;
/* buffer size needs to be a power of 2 */
static uint8_t Rx_Buffer[1 << 12];
static pthread_mutex_t Reader_Mutex, IOMutex;
#define _POSIX_SOURCE 1 /* POSIX compliant source */
static void *rs485_read_task(void *arg)
{
uint8_t buf[1 << 11];
int count, n;
fd_set input;
struct timeval cekalica;
FD_ZERO(&input);
FD_SET(RS485_Handle, &input);
cekalica.tv_sec = 1;
cekalica.tv_usec = 0;
for (;;) {
n = select(RS485_Handle + 1, &input, NULL, NULL, &cekalica);
if (n < 0) {
continue;
}
if (FD_ISSET(RS485_Handle, &input)) {
pthread_mutex_lock(&IOMutex);
count = read(RS485_Handle, buf, sizeof(buf));
pthread_mutex_unlock(&IOMutex);
if (count > 0) {
pthread_mutex_lock(&Reader_Mutex);
FIFO_Add(&Rx_FIFO, &buf[0], count);
pthread_mutex_unlock(&Reader_Mutex);
}
usleep(5000);
}
FD_SET(RS485_Handle, &input);
cekalica.tv_sec = 1;
cekalica.tv_usec = 0;
}
return NULL;
}
/*********************************************************************
* DESCRIPTION: Configures the interface name
* RETURN: none
* ALGORITHM: none
* NOTES: none
*********************************************************************/
void RS485_Set_Interface(char *ifname)
{
/* note: expects a constant char, or char from the heap */
if (ifname) {
RS485_Port_Name = ifname;
}
}
/*********************************************************************
* DESCRIPTION: Returns the interface name
* RETURN: none
* ALGORITHM: none
* NOTES: none
*********************************************************************/
const char *RS485_Interface(void)
{
return RS485_Port_Name;
}
/****************************************************************************
* DESCRIPTION: Returns the baud rate that we are currently running at
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
uint32_t RS485_Get_Baud_Rate(void)
{
switch (RS485_Baud) {
case B19200:
return 19200;
case B38400:
return 38400;
case B57600:
return 57600;
case B115200:
return 115200;
default:
case B9600:
return 9600;
}
}
/****************************************************************************
* DESCRIPTION: Sets the baud rate for the chip USART
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
bool RS485_Set_Baud_Rate(uint32_t baud)
{
bool valid = true;
switch (baud) {
case 9600:
RS485_Baud = B9600;
break;
case 19200:
RS485_Baud = B19200;
break;
case 38400:
RS485_Baud = B38400;
break;
case 57600:
RS485_Baud = B57600;
break;
case 115200:
RS485_Baud = B115200;
break;
default:
valid = false;
break;
}
if (valid) {
/* FIXME: store the baud rate */
}
return valid;
}
/* Transmits a Frame on the wire */
void RS485_Send_Frame(volatile struct mstp_port_struct_t *mstp_port, /* port specific data */
uint8_t * buffer, /* frame to send (up to 501 bytes of data) */
uint16_t nbytes)
{ /* number of bytes of data (up to 501) */
ssize_t written = 0;
int greska;
/*
On success, the number of bytes written are returned (zero indicates
nothing was written). On error, -1 is returned, and errno is set
appropriately. If count is zero and the file descriptor refers to a
regular file, 0 will be returned without causing any other effect. For
a special file, the results are not portable.
*/
pthread_mutex_lock(&IOMutex);
written = write(RS485_Handle, buffer, nbytes);
pthread_mutex_unlock(&IOMutex);
greska = errno;
if (written <= 0)
printf("write error: %s\n", strerror(greska));
/* tcdrain(RS485_Handle); */
/* per MSTP spec, sort of */
if (mstp_port) {
mstp_port->SilenceTimerReset();
}
return;
}
/* called by timer, interrupt(?) or other thread */
void RS485_Check_UART_Data(volatile struct mstp_port_struct_t *mstp_port)
{
if (mstp_port->ReceiveError == true) {
/* wait for state machine to clear this */
/*mstp_port->ReceiveError=false; */
return;
}
/* wait for state machine to read from the DataRegister */
/*else */
if (mstp_port->DataAvailable == false) {
/* check for data */
pthread_mutex_lock(&Reader_Mutex);
if (FIFO_Count(&Rx_FIFO) > 0) {
mstp_port->DataRegister = FIFO_Get(&Rx_FIFO);
mstp_port->DataAvailable = true;
}
pthread_mutex_unlock(&Reader_Mutex);
}
}
void RS485_Cleanup(void)
{
/* restore the old port settings */
tcsetattr(RS485_Handle, TCSANOW, &RS485_oldtio);
close(RS485_Handle);
pthread_mutex_destroy(&Reader_Mutex);
pthread_mutex_destroy(&IOMutex);
}
void RS485_Initialize(void)
{
struct termios newtio;
unsigned long hThread = 0;
printf("RS485: Initializing %s", RS485_Port_Name);
/*
Open device for reading and writing.
Blocking mode - more CPU effecient
*/
RS485_Handle = open(RS485_Port_Name, O_RDWR | O_NOCTTY /*| O_NDELAY */ );
if (RS485_Handle < 0) {
perror(RS485_Port_Name);
exit(-1);
}
#if 0
/* non blocking for the read */
fcntl(RS485_Handle, F_SETFL, FNDELAY);
#else
/* efficient blocking for the read */
fcntl(RS485_Handle, F_SETFL, 0);
#endif
/* save current serial port settings */
tcgetattr(RS485_Handle, &RS485_oldtio);
/* clear struct for new port settings */
bzero(&newtio, sizeof(newtio));
/*
BAUDRATE: Set bps rate. You could also use cfsetispeed and cfsetospeed.
CRTSCTS : output hardware flow control (only used if the cable has
all necessary lines. See sect. 7 of Serial-HOWTO)
CS8 : 8n1 (8bit,no parity,1 stopbit)
CLOCAL : local connection, no modem contol
CREAD : enable receiving characters
*/
newtio.c_cflag = RS485_Baud | CS8 | CLOCAL | CREAD | RS485MOD;
/* Raw input */
newtio.c_iflag = 0;
/* Raw output */
newtio.c_oflag = 0;
/* no processing */
newtio.c_lflag = 0;
/* activate the settings for the port after flushing I/O */
tcsetattr(RS485_Handle, TCSAFLUSH, &newtio);
/* destructor */
atexit(RS485_Cleanup);
/* flush any data waiting */
usleep(200000);
tcflush(RS485_Handle, TCIOFLUSH);
/* ringbuffer */
FIFO_Init(&Rx_FIFO, Rx_Buffer, sizeof(Rx_Buffer));
pthread_mutex_init(&Reader_Mutex, NULL);
pthread_mutex_init(&IOMutex, NULL);
pthread_create(&hThread, NULL, rs485_read_task, NULL);
printf("=success!\n");
}
#ifdef TEST_RS485
#include <string.h>
int main(int argc,
char *argv[])
{
uint8_t buf[8];
char *wbuf = { "BACnet!" };
size_t wlen = strlen(wbuf) + 1;
unsigned i = 0;
size_t written = 0;
int rlen;
/* argv has the "/dev/ttyS0" or some other device */
if (argc > 1) {
RS485_Set_Interface(argv[1]);
}
RS485_Set_Baud_Rate(38400);
RS485_Initialize();
for (;;) {
written = write(RS485_Handle, wbuf, wlen);
rlen = read(RS485_Handle, buf, sizeof(buf));
/* print any characters received */
if (rlen > 0) {
for (i = 0; i < rlen; i++) {
fprintf(stderr, "%02X ", buf[i]);
}
}
}
return 0;
}
#endif
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