1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <sys/mman.h> 4 #include <fcntl.h> 5 #include <string.h> 6 7 static int usage() 8 { 9 fprintf(stderr,"r [-b|-s] <address> [<value>]\n"); 10 return -1; 11 } 12 13 int r_main(int argc, char *argv[]) 14 { 15 int width = 4, set = 0, fd; 16 unsigned addr, value, endaddr = 0; 17 unsigned long mmap_start, mmap_size; 18 void *page; 19 char *end; 20 21 if(argc < 2) return usage(); 22 23 if(!strcmp(argv[1], "-b")) { 24 width = 1; 25 argc--; 26 argv++; 27 } else if(!strcmp(argv[1], "-s")) { 28 width = 2; 29 argc--; 30 argv++; 31 } 32 33 if(argc < 2) return usage(); 34 addr = strtoul(argv[1], 0, 16); 35 36 end = strchr(argv[1], '-'); 37 if (end) 38 endaddr = strtoul(end + 1, 0, 16); 39 40 if (!endaddr) 41 endaddr = addr + width - 1; 42 43 if (endaddr <= addr) { 44 fprintf(stderr, "invalid end address\n"); 45 return -1; 46 } 47 48 if(argc > 2) { 49 set = 1; 50 value = strtoul(argv[2], 0, 16); 51 } 52 53 fd = open("/dev/mem", O_RDWR | O_SYNC); 54 if(fd < 0) { 55 fprintf(stderr,"cannot open /dev/mem\n"); 56 return -1; 57 } 58 59 mmap_start = addr & ~(PAGE_SIZE - 1); 60 mmap_size = endaddr - mmap_start + 1; 61 mmap_size = (mmap_size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1); 62 63 page = mmap(0, mmap_size, PROT_READ | PROT_WRITE, 64 MAP_SHARED, fd, mmap_start); 65 66 if(page == MAP_FAILED){ 67 fprintf(stderr,"cannot mmap region\n"); 68 return -1; 69 } 70 71 while (addr <= endaddr) { 72 switch(width){ 73 case 4: { 74 unsigned *x = (unsigned*) (((unsigned) page) + (addr & 4095)); 75 if(set) *x = value; 76 fprintf(stderr,"%08x: %08x\n", addr, *x); 77 break; 78 } 79 case 2: { 80 unsigned short *x = (unsigned short*) (((unsigned) page) + (addr & 4095)); 81 if(set) *x = value; 82 fprintf(stderr,"%08x: %04x\n", addr, *x); 83 break; 84 } 85 case 1: { 86 unsigned char *x = (unsigned char*) (((unsigned) page) + (addr & 4095)); 87 if(set) *x = value; 88 fprintf(stderr,"%08x: %02x\n", addr, *x); 89 break; 90 } 91 } 92 addr += width; 93 } 94 return 0; 95 } 96
