Linux在应用层读写寄存器的方法
可以通过操作/dev/mem设备文件,以及mmap函数,将寄存器的地址映射到用户空间,直接在应用层对寄存器进行操作,示例如下:
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 | #include <stdio.h> #include <stdlib.h> #include <time.h> #include <unistd.h> #include <fcntl.h> #include <unistd.h>  #include <sys/mman.h> #define AUDIO_REG_BASE  (0xB800E000) #define MAP_SIZE    0xFF  staticintdev_fd; intmain(intargc, char**argv) {    dev_fd = open("/dev/mem", O_RDWR | O_NDELAY);       if(dev_fd < 0)    {     printf("open(/dev/mem) failed.");       return0;   }     unsigned char*map_base=(unsigned char* )mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, dev_fd, AUDIO_REG_BASE );    printf("%x \n", *(volatileunsigned int*)(map_base+0x38)); //打印该寄存器地址的value  #if 1 // LINE IN   printf("%x \n", *(volatileunsigned int*)(map_base+0x30));    *(volatileunsigned int*)(map_base + 0x30) = 0x208121bc; //修改该寄存器地址的value   usleep(1000000);   *(volatileunsigned int*)(map_base + 0x30) &= ~(0x1<<16); //修改该寄存器地址的value   usleep(1000000);    printf("%x \n", *(volatileunsigned int*)(map_base+0x30)); #endif    if(dev_fd)     close(dev_fd);    munmap(map_base,MAP_SIZE);//解除映射关系    return0; }  | 
感谢阅读,希望能帮助到大家。
 搬瓦工中文网
搬瓦工中文网






