mmap程序备份

#include 
#include 
#include
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

void usage(int argc, char const *argv[])
{
    printf("%s r/w/b8 addr value/num \n",argv[0]);
}


typedef union 
{
    uint8_t b8[4];
    uint16_t b16[2];
    uint32_t b32;
} commType;


// 小端返回TRUE,大端返回FALSE
int checkCPUIsLittle()
{
    union w
    {
    int a;
    char b;
    }c;
    c.a = 1;
    return (c.b == 1); 
}




#define MMAP_LEN    1024


int main(int argc, char const *argv[])
{
    int pin=-1;
    int val=0;

    if(argc<3)
    {
        usage(argc,argv);
        return -1;
    }

    uint32_t num=1;
    if (argc == 4)
	{
		num = strtoul(argv[3], NULL, 0);
	}




    uint32_t addr=strtoul(argv[2],NULL,0);
    // 地址偏移对其到4字节
    uint32_t addr_4=addr&(~0x03);
    // 计算向前的偏移量
    uint32_t addr_offset=addr-addr_4;


    #define GPIO4   0x20A8000
    #define GPIO3   0x20A4000
    if (strcmp(argv[1], "g4") == 0)
    {
        addr_4=GPIO4;
        pin=strtoul(argv[2],NULL,0);
        val=strtoul(argv[3],NULL,0);
        addr_offset=0;
    } 
    else if (strcmp(argv[1], "g3") == 0)
    {
        addr_4=GPIO3;
        pin=strtoul(argv[2],NULL,0);
        val=strtoul(argv[3],NULL,0);
        
        addr_offset=0;
    }

    
    char dev_name[] = "/dev/mem";
    int fd  =  open(dev_name,O_RDWR);
    if(fd<0){
        printf("open %s is error\n",dev_name);
        return -1 ;
    } 
    unsigned char  * basePtr=mmap( 0, MMAP_LEN, PROT_READ | PROT_WRITE, MAP_SHARED,fd, addr_4);
    if(basePtr == NULL){
        printf("basePtr mmap is error\n");
        close(fd);
        return -1;
    }

	volatile unsigned char  *p8;
	volatile unsigned short *p16;
	volatile unsigned int   *p32;
    p8  = basePtr;
	p16 = (volatile unsigned short *)p8;
	p32 = (volatile unsigned int   *)p8;

    if (pin != -1)
    {
        // 寻找字节
        addr_offset=pin/8;

        

        //addr_offset 表示的就是第几个字节
        commType d;
        d.b32=*p32;

        d.b32&=~(1<

./b.out  w8 0x20A4002 0x09  #off
./b.out  w8 0x20A4002 0x89  #on