如何在linux内核模块中对串口进行读写

  1<sys types.h="">   
  2#include <sys stat.h="">   
  3#include <fcntl.h>   
  4#include <termios.h>   
  5#include <stdio.h>   
  6  
  7/* baudrate settings are defined in <asm termbits.h="">, which is   
  8included by <termios.h> */   
  9#define BAUDRATE B38400   
 10/* change this definition for the correct port */   
 11#define MODEMDEVICE "/dev/ttyS1"   
 12#define _POSIX_SOURCE 1 /* POSIX compliant source */   
 13  
 14#define FALSE 0   
 15#define TRUE 1   
 16  
 17volatile int STOP=FALSE;   
 18  
 19main()   
 20{   
 21int fd,c, res;   
 22struct termios oldtio,newtio;   
 23char buf[255];   
 24/*   
 25Open modem device for reading and writing and not as controlling tty   
 26because we don't want to get killed if linenoise sends CTRL-C.   
 27*/   
 28fd = open(MODEMDEVICE, O_RDWR ¦ O_NOCTTY );   
 29if (fd &lt;0) {perror(MODEMDEVICE); exit(-1); }   
 30  
 31tcgetattr(fd,&amp;oldtio); /* save current serial port settings */   
 32bzero(&amp;newtio, sizeof(newtio)); /* clear struct for new port settings */   
 33  
 34/*   
 35BAUDRATE: Set bps rate. You could also use cfsetispeed and cfsetospeed.   
 36CRTSCTS : output hardware flow control (only used if the cable has   
 37all necessary lines. See sect. 7 of Serial-HOWTO)   
 38CS8 : 8n1 (8bit,no parity,1 stopbit)   
 39CLOCAL : local connection, no modem contol   
 40CREAD : enable receiving characters   
 41*/   
 42newtio.c_cflag = BAUDRATE ¦ CRTSCTS ¦ CS8 ¦ CLOCAL ¦ CREAD;   
 43  
 44/*   
 45IGNPAR : ignore bytes with parity errors   
 46ICRNL : map CR to NL (otherwise a CR input on the other computer   
 47will not terminate input)   
 48otherwise make device raw (no other input processing)   
 49*/   
 50newtio.c_iflag = IGNPAR ¦ ICRNL;   
 51  
 52/*   
 53Raw output.   
 54*/   
 55newtio.c_oflag = 0;   
 56  
 57/*   
 58ICANON : enable canonical input   
 59disable all echo functionality, and don't send signals to calling program   
 60*/   
 61newtio.c_lflag = ICANON;   
 62  
 63/*   
 64initialize all control characters   
 65default values can be found in /usr/include/termios.h, and are given   
 66in the comments, but we don't need them here   
 67*/   
 68newtio.c_cc[VINTR] = 0; /* Ctrl-c */   
 69newtio.c_cc[VQUIT] = 0; /* Ctrl-\ */   
 70newtio.c_cc[VERASE] = 0; /* del */   
 71newtio.c_cc[VKILL] = 0; /* @ */   
 72newtio.c_cc[VEOF] = 4; /* Ctrl-d */   
 73newtio.c_cc[VTIME] = 0; /* inter-character timer unused */   
 74newtio.c_cc[VMIN] = 1; /* blocking read until 1 character arrives */   
 75newtio.c_cc[VSWTC] = 0; /* '\0' */   
 76newtio.c_cc[VSTART] = 0; /* Ctrl-q */   
 77newtio.c_cc[VSTOP] = 0; /* Ctrl-s */   
 78newtio.c_cc[VSUSP] = 0; /* Ctrl-z */   
 79newtio.c_cc[VEOL] = 0; /* '\0' */   
 80newtio.c_cc[VREPRINT] = 0; /* Ctrl-r */   
 81newtio.c_cc[VDISCARD] = 0; /* Ctrl-u */   
 82newtio.c_cc[VWERASE] = 0; /* Ctrl-w */   
 83newtio.c_cc[VLNEXT] = 0; /* Ctrl-v */   
 84newtio.c_cc[VEOL2] = 0; /* '\0' */   
 85  
 86/*   
 87now clean the modem line and activate the settings for the port   
 88*/   
 89tcflush(fd, TCIFLUSH);   
 90tcsetattr(fd,TCSANOW,&amp;newtio);   
 91  
 92/*   
 93terminal settings done, now handle input   
 94In this example, inputting a 'z' at the beginning of a line will   
 95exit the program.   
 96*/   
 97while (STOP==FALSE) { /* loop until we have a terminating condition */   
 98/* read blocks program execution until a line terminating character is   
 99input, even if more than 255 chars are input. If the number   
100of characters read is smaller than the number of chars available,   
101subsequent reads will return the remaining chars. res will be set   
102to the actual number of characters actually read */   
103res = read(fd,buf,255);   
104buf[res]=0; /* set end of string, so we can printf */   
105printf(":%s:%d\n", buf, res);   
106if (buf[0]=='z') STOP=TRUE;   
107}   
108/* restore the old port settings */   
109tcsetattr(fd,TCSANOW,&amp;oldtio);   
110}</termios.h></asm></stdio.h></termios.h></fcntl.h></sys></sys>