Thank for your detailed reply.
I could hook-up SIGIO handler and see handler getting called when there is data on respective UART. but I have few issues:
1. SIGIO handler gets called only when bunch of bytes are available (not on each byte)
2. SIGIO getting called without missing as long as I had only UART_B, when I added UART_C also, i see inconsistency and data loss in handler.
3. I use Colibri iMX7d (emmc) evl board, I can use only 2 UART (B and C), not sure how and what to modify in device tree and rebuild bitbake to get all UART /dev/ttymx3 to 7
Pasting my code:
#define BAUDRATE B115200
#define COMM_PORT_B "/dev/ttymxc1"
#define COMM_PORT_C "/dev/ttymxc1"
#define COMM_PORT_D "/dev/ttymxc1"
#define NO_OF_UART 2
static int fd[NO_OF_UART] = {0};
static int max_fds = 0;
static fd_set read_fd;
static char comm_port[NO_OF_UART][16] = {
{COMM_PORT_B},
{COMM_PORT_C},
// {COMM_PORT_D},
};
static uint8_t uart_buf[UART_DATA_LEN];
volatile uint8_t uart_flag;
static void UART_INT (int sig)
{
char rx_buf[UART_DATA_LEN] = {'\0'};
int res = 0;
int i = 0;
for(i = 0; i < NO_OF_UART; i++)
{
if(FD_ISSET(fd[i], &read_fd)) {
res = read(fd[i], &rx_buf, UART_DATA_LEN);
if(res > 0) {
//data received, copy into buffer with flag and clear the buffer
uart_flag |= (1<<i); //set respective flag
memcpy(uart_buf, rx_buf, res);
memset(rx_buf, '\0', UART_DATA_LEN);
}
}
}
}
int init_uart(int *fd, const char *port)
{
int rc = 0;
char cmd[CMD_STR_LEN] = {'\0'};
struct termios newtio;
struct sigaction saio;
sprintf(cmd, "stty -F %s 115200 -echo", port);
system(cmd);
memset(cmd, '\0', CMD_STR_LEN);
sprintf(cmd, "cat < %s &", port);
system(cmd);
*fd = open(port, O_RDWR | O_NOCTTY | O_NONBLOCK);
if(*fd < 0) {
perror(port);
exit(-1);
}
saio.sa_handler = UART_INT;
sigemptyset(&saio.sa_mask);
saio.sa_flags = SA_SIGINFO;
sigaction(SIGIO, &saio,NULL);
fcntl (*fd, F_SETOWN, getgid());
fcntl(*fd, F_SETFL, FASYNC);
newtio.c_cflag = BAUDRATE | CS8 | CLOCAL | CREAD ;
newtio.c_iflag = IGNPAR | IXOFF;
newtio.c_oflag = 0;
newtio.c_lflag = 0;
newtio.c_cc[VMIN] = 0;
newtio.c_cc[VTIME] = 0;
tcflush(*fd, TCIFLUSH);
tcsetattr(*fd, TCSANOW, &newtio);
return rc;
}
static uint8_t cal_crc(uint8_t *byte, size_t len)
{
uint8_t crc = 0xFF;
size_t i, j;
for(i = 0; i < len; i++)
{
crc ^= byte[i];
for(j = 0; j < 8; j++)
{
if((crc & 0x80) != 0) {
crc = (uint8_t) ((crc << 1) ^ 0x31);
} else {
crc <<= 1;
}
}
}
return crc;
}
int send_data(int fd, uint8_t *buf)
{
int rc = 0;
int size = buf[NO_OF_BYTES] + 2;
buf[size] = cal_crc(buf,buf[NO_OF_BYTES] + 1);
rc = write(fd, (char *)buf, size);
return rc;
}
// Keep reentrant as this function runs in serveral instances
static int uart_trigger(void *index)
{
int rc = 0;
do
{
FD_SET(fd[*(int *)index], &read_fd);
pselect(max_fds + 1, &read_fd, NULL, NULL, NULL, NULL);
}while(1);
return rc;
}
static int largest_num(int arr[], int n)
{
int i;
int max = arr[0];
for(i = 1; i < n; i++)
{
if(arr[i] > max) {
max = arr[i];
}
}
return max;
}
int uart_main(void *td)
{
int rc = 0;
int mydata = *(int *)td;
int i = 0;
pthread_t thread_id[NO_OF_UART];
int tr = 0;
int arg[NO_OF_UART] = {0};
printf("%s() called thread ID: %d\n", __FUNCTION__, mydata);
for(i = 0; i < NO_OF_UART; i++) {
init_uart(&fd[i], comm_port[i]);
}
//calculate max fds
max_fds = largest_num(fd, NO_OF_UART);
FD_ZERO(&read_fd);
for(i = 0; i < NO_OF_UART; i++) {
arg[i] = i;
rc |= pthread_create(&(thread_id[i]), NULL, (void *) uart_trigger, (void *)&arg[i]);
}
do {
switch(uart_flag)
{
case UART_B_DATA:
printf("UART_B: %s\n", uart_buf);
memset(uart_buf, '\0', UART_DATA_LEN);
uart_flag &= ~UART_B_DATA;
break;
case UART_C_DATA:
printf("UART_C: %s\n", uart_buf);
memset(uart_buf, '\0', UART_DATA_LEN);
uart_flag &= ~UART_C_DATA;
break;
}
}while(1);
for(i = 0; i < NO_OF_UART; i++) {
rc |=pthread_join(thread_id[i], (void **)&tr);
printf("Thread: %d %s\n", i, tr==0?"SUCCESS":"FAILED");
}
return rc;
}
Please suggest me on this....
