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bacnet_stack/ports/linux/rs485.c
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Kari Argillander cb243c36a8 Improve SPDX identifier coverage (#716) 
* Change MIT license texts to SPDX-License-Identifier

SPDX-License-Identifier is much easier to understand and grep than
license text so use that instead.

* Change GPL exception license texts to SPDX-License-Identifier

SPDX-License-Identifier is much easier to understand and grep than
license text so use that instead.

* Change misc license texts to SPDX-License-Identifier

There are some external code in repo which are not licenses as most of
the stuff in this repo. We still want every file to have SPDX identifier
to easily grep licenses.

* Add currently used license files

Even though Bacnet-Stack is using SPDX identifiers we still need to give
those license files with source. For this reason add all license files
to license/ folder.

SPDX has also files which would make same thing but this is style which
example Linux kernel is using and it is quite clear so I choose that one
for now.

I choosed not yet bring CC-PDDC as that is not right license for those
files.

---------

Co-authored-by: Kari Argillander <kari.argillander@fidelix.com>
2024-08-12 15:33:02 -05:00

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/**************************************************************************
*
* Copyright (C) 2007 Steve Karg <skarg@users.sourceforge.net>
* Updated by Nikola Jelic 2011 <nikola.jelic@euroicc.com>
*
* SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0
*
*********************************************************************/
/** @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>
#include <linux/serial.h> /* for struct serial_struct */
#include <math.h> /* for calculation of custom divisor */
#include <sys/ioctl.h>
/* for scandir */
#include <dirent.h>
/* for basename */
#include <libgen.h>
/* Local includes */
#include "bacnet/datalink/mstp.h"
#include "rs485.h"
#include "bacnet/basic/sys/fifo.h"
#include <sys/select.h>
#include <sys/time.h>
#include "dlmstp_linux.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;
/* for setting custom divisor */
static struct serial_struct RS485_oldserial;
/* indicator of special baud rate */
static bool RS485_SpecBaud = false;
/* 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[4096];
#define _POSIX_SOURCE 1 /* POSIX compliant source */
/*********************************************************************
* 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)
{
uint32_t baud = 0;
switch (RS485_Baud) {
case B0:
baud = 0;
break;
case B50:
baud = 50;
break;
case B75:
baud = 75;
break;
case B110:
baud = 110;
break;
case B134:
baud = 134;
break;
case B150:
baud = 150;
break;
case B200:
baud = 200;
break;
case B300:
baud = 300;
break;
case B600:
baud = 600;
break;
case B1200:
baud = 1200;
break;
case B1800:
baud = 1800;
break;
case B2400:
baud = 2400;
break;
case B4800:
baud = 4800;
break;
case B9600:
baud = 9600;
break;
case B19200:
baud = 19200;
break;
case B38400:
if (!RS485_SpecBaud) {
/* Linux asks for custom divisor
only when baud is set on 38400 */
baud = 38400;
} else {
baud = 76800;
}
break;
case B57600:
baud = 57600;
break;
case B115200:
baud = 115200;
break;
case B230400:
baud = 230400;
break;
default:
baud = 9600;
}
return baud;
}
/****************************************************************************
* DESCRIPTION: Returns the baud rate that we are currently running at
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
uint32_t RS485_Get_Port_Baud_Rate(struct mstp_port_struct_t *mstp_port)
{
uint32_t baud = 0;
SHARED_MSTP_DATA *poSharedData = (SHARED_MSTP_DATA *)mstp_port->UserData;
if (!poSharedData) {
return 0;
}
switch (poSharedData->RS485_Baud) {
case B0:
baud = 0;
break;
case B50:
baud = 50;
break;
case B75:
baud = 75;
break;
case B110:
baud = 110;
break;
case B134:
baud = 134;
break;
case B150:
baud = 150;
break;
case B200:
baud = 200;
break;
case B300:
baud = 300;
break;
case B600:
baud = 600;
break;
case B1200:
baud = 1200;
break;
case B1800:
baud = 1800;
break;
case B2400:
baud = 2400;
break;
case B4800:
baud = 4800;
break;
case B9600:
baud = 9600;
break;
case B19200:
baud = 19200;
break;
case B38400:
baud = 38400;
break;
case B57600:
baud = 57600;
break;
case B115200:
baud = 115200;
break;
case B230400:
baud = 230400;
break;
default:
baud = 9600;
break;
}
return baud;
}
/****************************************************************************
* 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;
RS485_SpecBaud = false;
switch (baud) {
case 0:
RS485_Baud = B0;
break;
case 50:
RS485_Baud = B50;
break;
case 75:
RS485_Baud = B75;
break;
case 110:
RS485_Baud = B110;
break;
case 134:
RS485_Baud = B134;
break;
case 150:
RS485_Baud = B150;
break;
case 200:
RS485_Baud = B200;
break;
case 300:
RS485_Baud = B300;
break;
case 600:
RS485_Baud = B600;
break;
case 1200:
RS485_Baud = B1200;
break;
case 1800:
RS485_Baud = B1800;
break;
case 2400:
RS485_Baud = B2400;
break;
case 4800:
RS485_Baud = B4800;
break;
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 76800:
RS485_Baud = B38400;
RS485_SpecBaud = true;
break;
case 115200:
RS485_Baud = B115200;
break;
case 230400:
RS485_Baud = B230400;
break;
default:
valid = false;
break;
}
if (valid) {
/* FIXME: store the baud rate */
}
return valid;
}
/****************************************************************************
* DESCRIPTION: Transmit a frame on the wire
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Send_Frame(
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) */
uint32_t turnaround_time = Tturnaround * 1000;
uint32_t baud;
ssize_t written = 0;
int greska;
SHARED_MSTP_DATA *poSharedData = NULL;
if (mstp_port) {
poSharedData = (SHARED_MSTP_DATA *)mstp_port->UserData;
}
if (!poSharedData) {
baud = RS485_Get_Baud_Rate();
/* sleeping for turnaround time is necessary to give other devices
time to change from sending to receiving state. */
usleep(turnaround_time / baud);
/*
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.
*/
written = write(RS485_Handle, buffer, nbytes);
greska = errno;
if (written <= 0) {
printf("write error: %s\n", strerror(greska));
} else {
/* wait until all output has been transmitted. */
tcdrain(RS485_Handle);
}
/* tcdrain(RS485_Handle); */
/* per MSTP spec, sort of */
if (mstp_port) {
mstp_port->SilenceTimerReset((void *)mstp_port);
}
} else {
baud = RS485_Get_Port_Baud_Rate(mstp_port);
/* sleeping for turnaround time is necessary to give other devices
time to change from sending to receiving state. */
usleep(turnaround_time / baud);
/*
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.
*/
written = write(poSharedData->RS485_Handle, buffer, nbytes);
greska = errno;
if (written <= 0) {
printf("write error: %s\n", strerror(greska));
} else {
/* wait until all output has been transmitted. */
tcdrain(poSharedData->RS485_Handle);
}
/* tcdrain(RS485_Handle); */
/* per MSTP spec, sort of */
if (mstp_port) {
mstp_port->SilenceTimerReset((void *)mstp_port);
}
}
return;
}
/****************************************************************************
* DESCRIPTION: Get a byte of receive data
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Check_UART_Data(struct mstp_port_struct_t *mstp_port)
{
fd_set input;
struct timeval waiter;
uint8_t buf[2048];
int n;
SHARED_MSTP_DATA *poSharedData = (SHARED_MSTP_DATA *)mstp_port->UserData;
if (!poSharedData) {
if (mstp_port->ReceiveError == true) {
/* do nothing but wait for state machine to clear the error */
/* burning time, so wait a longer time */
waiter.tv_sec = 0;
waiter.tv_usec = 5000;
} else if (mstp_port->DataAvailable == false) {
/* wait for state machine to read from the DataRegister */
if (FIFO_Count(&Rx_FIFO) > 0) {
/* data is available */
mstp_port->DataRegister = FIFO_Get(&Rx_FIFO);
mstp_port->DataAvailable = true;
/* FIFO is giving data - just poll */
waiter.tv_sec = 0;
waiter.tv_usec = 0;
} else {
/* FIFO is empty - wait a longer time */
waiter.tv_sec = 0;
waiter.tv_usec = 5000;
}
}
/* grab bytes and stuff them into the FIFO every time */
FD_ZERO(&input);
FD_SET(RS485_Handle, &input);
n = select(RS485_Handle + 1, &input, NULL, NULL, &waiter);
if (n < 0) {
return;
}
if (FD_ISSET(RS485_Handle, &input)) {
n = read(RS485_Handle, buf, sizeof(buf));
FIFO_Add(&Rx_FIFO, &buf[0], n);
}
} else {
if (mstp_port->ReceiveError == true) {
/* do nothing but wait for state machine to clear the error */
/* burning time, so wait a longer time */
waiter.tv_sec = 0;
waiter.tv_usec = 5000;
} else if (mstp_port->DataAvailable == false) {
/* wait for state machine to read from the DataRegister */
if (FIFO_Count(&poSharedData->Rx_FIFO) > 0) {
/* data is available */
mstp_port->DataRegister = FIFO_Get(&poSharedData->Rx_FIFO);
mstp_port->DataAvailable = true;
/* FIFO is giving data - just poll */
waiter.tv_sec = 0;
waiter.tv_usec = 0;
} else {
/* FIFO is empty - wait a longer time */
waiter.tv_sec = 0;
waiter.tv_usec = 5000;
}
}
/* grab bytes and stuff them into the FIFO every time */
FD_ZERO(&input);
FD_SET(poSharedData->RS485_Handle, &input);
n = select(poSharedData->RS485_Handle + 1, &input, NULL, NULL, &waiter);
if (n < 0) {
return;
}
if (FD_ISSET(poSharedData->RS485_Handle, &input)) {
n = read(poSharedData->RS485_Handle, buf, sizeof(buf));
FIFO_Add(&poSharedData->Rx_FIFO, &buf[0], n);
}
}
}
void RS485_Cleanup(void)
{
/* restore the old port settings */
tcsetattr(RS485_Handle, TCSANOW, &RS485_oldtio);
ioctl(RS485_Handle, TIOCSSERIAL, &RS485_oldserial);
close(RS485_Handle);
}
void RS485_Initialize(void)
{
struct termios newtio;
struct serial_struct newserial;
float baud_error = 0.0;
#if PRINT_ENABLED
fprintf(stdout, "RS485 Interface: %s\n", RS485_Port_Name);
#endif
/*
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);
/* we read the old serial setup */
ioctl(RS485_Handle, TIOCGSERIAL, &RS485_oldserial);
/* we need a copy of existing settings */
memcpy(&newserial, &RS485_oldserial, sizeof(struct serial_struct));
/* 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);
if (RS485_SpecBaud) {
/* 76800, custom divisor must be set */
newserial.flags |= ASYNC_SPD_CUST;
newserial.custom_divisor = round(((float)newserial.baud_base) / 76800);
/* we must check that we calculated some sane value;
small baud bases yield bad custom divisor values */
baud_error = fabs(1 -
((float)newserial.baud_base) / ((float)newserial.custom_divisor) /
76800);
if ((newserial.custom_divisor == 0) || (baud_error > 0.02)) {
/* bad divisor */
fprintf(stderr, "RS485 bad custom divisor %d, base baud %d\n",
newserial.custom_divisor, newserial.baud_base);
exit(EXIT_FAILURE);
}
/* if all goes well, set new divisor */
ioctl(RS485_Handle, TIOCSSERIAL, &newserial);
}
#if PRINT_ENABLED
fprintf(stdout, "RS485 Baud Rate %u\n", RS485_Get_Baud_Rate());
fflush(stdout);
#endif
/* destructor */
atexit(RS485_Cleanup);
/* flush any data waiting */
usleep(200000);
tcflush(RS485_Handle, TCIOFLUSH);
/* ringbuffer */
FIFO_Init(&Rx_FIFO, Rx_Buffer, sizeof(Rx_Buffer));
}
/* Print in a format for Wireshark ExtCap */
void RS485_Print_Ports(void)
{
int n;
struct dirent **namelist;
const char *sysdir = "/sys/class/tty/";
struct stat st;
char buffer[1024];
char device_dir[1024];
char *driver_name = NULL;
int fd = 0;
bool valid_port = false;
struct serial_struct serinfo;
/* Scan through /sys/class/tty -
it contains all tty-devices in the system */
n = scandir(sysdir, &namelist, NULL, NULL);
if (n < 0) {
perror("RS485: scandir");
} else {
while (n--) {
if (strcmp(namelist[n]->d_name, "..") &&
strcmp(namelist[n]->d_name, ".")) {
snprintf(device_dir, sizeof(device_dir), "%s%s/device", sysdir,
namelist[n]->d_name);
/* Stat the devicedir and handle it if it is a symlink */
if (lstat(device_dir, &st) == 0 && S_ISLNK(st.st_mode)) {
memset(buffer, 0, sizeof(buffer));
snprintf(device_dir, sizeof(device_dir),
"%s%s/device/driver", sysdir, namelist[n]->d_name);
if (readlink(device_dir, buffer, sizeof(buffer)) > 0) {
valid_port = false;
driver_name = basename(buffer);
if (strcmp(driver_name, "serial8250") == 0) {
/* serial8250-devices must be probed */
snprintf(device_dir, sizeof(device_dir), "/dev/%s",
namelist[n]->d_name);
fd = open(
device_dir, O_RDWR | O_NONBLOCK | O_NOCTTY);
if (fd >= 0) {
/* Get serial_info */
if (ioctl(fd, TIOCGSERIAL, &serinfo) == 0) {
/* If device type is not PORT_UNKNOWN */
/* we accept the port */
if (serinfo.type != PORT_UNKNOWN) {
valid_port = true;
}
}
close(fd);
}
} else {
valid_port = true;
}
if (valid_port) {
/* print full absolute file path */
printf("interface {value=/dev/%s}"
"{display=MS/TP Capture on /dev/%s}\n",
namelist[n]->d_name, namelist[n]->d_name);
}
}
}
}
free(namelist[n]);
}
free(namelist);
}
}
#ifdef TEST_RS485
#include <string.h>
int main(int argc, char *argv[])
{
struct mstp_port_struct_t mstp_port = { 0 };
uint8_t token_buf[8] = { 0x55, 0xFF, 0x00, 0x7E, 0x07, 0x00, 0x00, 0xFD };
uint8_t pfm_buf[8] = { 0x55, 0xFF, 0x01, 0x67, 0x07, 0x00, 0x00, 0x3E };
long baud = 38400;
bool write_token = false;
bool write_pfm = false;
/* argv has the "/dev/ttyS0" or some other device */
if (argc > 1) {
RS485_Set_Interface(argv[1]);
}
if (argc > 2) {
baud = strtol(argv[2], NULL, 0);
}
if (argc > 3) {
if (strcmp("token", argv[3]) == 0) {
write_token = true;
}
if (strcmp("pfm", argv[3]) == 0) {
write_pfm = true;
}
}
RS485_Set_Baud_Rate(baud);
RS485_Initialize();
for (;;) {
if (write_token) {
RS485_Send_Frame(NULL, token_buf, sizeof(token_buf));
usleep(25000);
} else if (write_pfm) {
RS485_Send_Frame(NULL, pfm_buf, sizeof(pfm_buf));
usleep(100000);
} else {
RS485_Check_UART_Data(&mstp_port);
if (mstp_port.DataAvailable) {
fprintf(stderr, "%02X ", mstp_port.DataRegister);
mstp_port.DataAvailable = false;
}
}
}
return 0;
}
#endif
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