Linux/AM3352: UART1 read issue

#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>        
#include <stdlib.h> 
#define BAUDRATE B9600 
#define MODEMDEVICE "/dev/ttyS1"/*UART NAME IN PROCESSOR*/
#define _POSIX_SOURCE 1 /* POSIX compliant source */
#define FALSE 0
#define TRUE 1
void openport(void);
void sendport(void);
void readport(void);
int fd=0, n = 0;
static int cnt, size, s_cnt;
unsigned char *var;
struct termios oldtp, newtp;
char sendcmd1[10]="\0";
FILE *file;
 
void  readport(void)
{
	unsigned char buff;
	file = fopen( "zname.txt", "w+" );
	while (1) 
	{ 
  		n = read(fd, &buff, 1);
		printf("Total no of Bytes Read %d\n", n);
		//fcntl(fd,F_SETFL,0);
 		if (n == -1)
		{
			switch(errno)
			{
         			case EAGAIN: /* sleep() */ 
            			continue;
          
         			default: goto quit;
         		}
		}

  		if (n == 0)
		{
			break;
		}
  
		fputc(buff, file);
  		printf("%d %c\n", n,buff);
  	}
quit:
   fclose (file);
}

void openport(void)
{
         
	 fd = open(MODEMDEVICE, O_RDWR | O_NOCTTY |O_NDELAY );
	 printf("oviya :%d\n",fd);
         if (fd <0)
         {
         	perror(MODEMDEVICE);
 
         }
                                                                                
         fcntl(fd,F_SETFL,0);
         tcgetattr(fd,&oldtp); /* save current serial port settings */
    //     tcgetattr(fd,&newtp); /* save current serial port settings */
         bzero(&newtp, sizeof(newtp));
  //       bzero(&oldtp, sizeof(oldtp));
                                                                                
         newtp.c_cflag = BAUDRATE | CRTSCTS | CS8 | CLOCAL | CREAD;
                                                                                
         newtp.c_iflag = IGNPAR | ICRNL;
                                                                                
         newtp.c_oflag = 0;                                                                        
         newtp.c_lflag = ICANON;                                                                    
         newtp.c_cc[VINTR]    = 0;     /* Ctrl-c */
         newtp.c_cc[VQUIT]    = 0;     /* Ctrl-\ */
         newtp.c_cc[VERASE]   = 0;     /* del */
         newtp.c_cc[VKILL]    = 0;     /* @ */
        // newtp.c_cc[VEOF]     = 4;     /* Ctrl-d */
         newtp.c_cc[VTIME]    = 0;     /* inter-character timer unused */
         newtp.c_cc[VMIN]     = 0;     /* blocking read until 1 character arrives */
         newtp.c_cc[VSWTC]    = 0;     /* '\0' */
         newtp.c_cc[VSTART]   = 0;     /* Ctrl-q */
         newtp.c_cc[VSTOP]    = 0;     /* Ctrl-s */
         newtp.c_cc[VSUSP]    = 0;     /* Ctrl-z */
         newtp.c_cc[VEOL]     = 0;     /* '\0' */
         newtp.c_cc[VREPRINT] = 0;     /* Ctrl-r */
         newtp.c_cc[VDISCARD] = 0;     /* Ctrl-u */
         newtp.c_cc[VWERASE]  = 0;     /* Ctrl-w */
         newtp.c_cc[VLNEXT]   = 0;     /* Ctrl-v */
         newtp.c_cc[VEOL2]    = 0;     /* '\0' */
   	                                                                                                                                             
//	  tcflush(fd, TCIFLUSH);
//	 tcsetattr(fd,TCSANOW,&newtp);
 
}

int  main()
{
	openport();
	readport();
        return 0;
}