Add watchdog.c to examples

examples/Makefile

@@ -49,7 +49,8 @@ SRC	=	blink.c blink8.c blink12.c					\
 		lowPower.c							\
 		max31855.c							\
 		rht03.c								\
-		w25q64_test.c oled_demo.c spiSpeed.c
+		w25q64_test.c oled_demo.c spiSpeed.c				\
+		watchdog.c
 
 OBJ	=	$(SRC:.c=.o)
 
@@ -158,6 +159,10 @@ w25q64_test:	w25q64_test.o
 	$Q echo [link]
 	$Q $(CC) -o $@ w25q64_test.o $(LDFLAGS) $(LDLIBS)
 
+watchdog:	watchdog.o
+	$Q echo [link]
+	$Q $(CC) -o $@ watchdog.o $(LDFLAGS) $(LDLIBS)
+
 oled_demo:	oled_demo.o
 	$Q echo [link]
 	$Q $(CC) -o $@ oled_demo.o $(LDFLAGS) $(LDLIBS)

examples/watchdog.c

@@ -0,0 +1,115 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <errno.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <time.h>
+#include <getopt.h>
+#include <sys/signal.h>
+#include <termios.h>
+
+struct watchdog_info{
+    unsigned int options;   //options the card/driver supprots 19        
+    unsigned int firmware_version;  //firmcard version of the card
+    unsigned char identity[32];     //identity of the board 21
+ };
+
+#define WATCHDOG_IOCTL_BASE 'W'
+#define WDIOC_GETSUPPORT _IOR(WATCHDOG_IOCTL_BASE, 0, struct watchdog_info)
+#define WDIOC_SETTIMEOUT _IOWR(WATCHDOG_IOCTL_BASE, 6, int)
+#define WDIOC_GETTIMEOUT _IOR(WATCHDOG_IOCTL_BASE, 7, int) //27
+#define WDIOS_DISABLECARD 0x0001       
+#define WDIOS_ENABLECARD 0x0002
+#define WDIOC_SETOPTIONS _IOR(WATCHDOG_IOCTL_BASE, 4, int)
+#define WDIOC_KEEPALIVE _IOR(WATCHDOG_IOCTL_BASE, 5, int)
+
+int Getch (void)   //无回显的从屏幕输入字符，来达到喂狗的目的
+
+{
+
+     int ch;
+     struct termios oldt, newt;   //终端设备结构体
+     tcgetattr(STDIN_FILENO, &oldt);   //获得终端属性
+     newt = oldt;
+     newt.c_lflag &= ~(ECHO|ICANON);   //设置无回显属性
+     tcsetattr(STDIN_FILENO, TCSANOW, &newt);  //设置新的终端属性
+     ch = getchar();   //从键盘输入一个数据
+     tcsetattr(STDIN_FILENO, TCSANOW, &oldt);  //恢复终端设备初始设置
+     return ch;
+
+}
+ //suspend some seconds
+int zsleep(int millisecond)
+
+{
+     unsigned long usec;
+     usec=1000*millisecond;
+     usleep(usec); //usleep(1)睡眠一微秒（10E-6),这里也就是0.1s
+}
+int Init()
+{
+     int fd;
+     //open device file
+     fd = open("/dev/watchdog",O_RDWR);   //打开看门狗设备
+      if(fd < 0)
+     {
+         printf("device open fail\n");
+         return -1;
+     }
+     printf("open success\n");
+     return fd;
+}
+
+int main(int argc,char **argv)
+{
+     int fd,ch;
+     int i,j;
+     char c;
+     struct watchdog_info wi;
+	 if(argc != 2){
+		 printf("Usage : ./watchdog 10\n");
+		 return -1;
+	 }
+     fd=Init();  //打开终端看门狗设备
+	 ioctl(fd, WDIOC_SETOPTIONS, WDIOS_ENABLECARD); 
+     //读板卡信息，但不常用
+     ioctl(fd,WDIOC_GETSUPPORT,&wi);
+     printf("options is %d,identity is %s\n",wi.options,wi.identity);
+     //读看门狗溢出时间
+
+     printf("put_usr return,if 0,success:%d\n",ioctl(fd,WDIOC_GETTIMEOUT,&i));
+
+	 printf("The old reset time is: %d\n", i);
+     //关闭
+      i=WDIOS_DISABLECARD;//WDIOC_SETOPTIONS=0X0001
+     printf("return ENOTTY,if -1,success:%d\n",ioctl(fd,WDIOC_SETOPTIONS,&i));
+     //打开
+      i=WDIOS_ENABLECARD;//WDIOS_ENABLECARD 0x0002
+     printf("return ENOTTY,if -1,success:%d\n",ioctl(fd,WDIOC_SETOPTIONS,&i));
+     i=atoi(argv[1]);
+     printf("put_user return,if 0,success:%d\n",ioctl(fd,WDIOC_SETTIMEOUT,&i));
+     //读新的设置时间
+
+     printf("put_usr return,if 0,success:%d\n",ioctl(fd,WDIOC_GETTIMEOUT,&i));
+
+
+     while(1)
+     {
+           zsleep(100);
+           if((c=Getch())!=27){
+                //输入如果不是ESC，就喂狗，否则不喂狗，到时间后系统重启
+        printf("keep alive \n");
+                ioctl(fd,WDIOC_KEEPALIVE,NULL);
+                //write(fd,NULL,1);     //同样是喂狗
+
+           }
+     }
+    close(fd);   //关闭设备
+     return 0;
+}