diff options
| -rw-r--r-- | devmem2.c | 109 |
1 files changed, 61 insertions, 48 deletions
@@ -50,26 +50,31 @@ #include <sys/mman.h> #include <stdint.h> #include <inttypes.h> - -#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \ - __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0) - + +#define FATAL \ + do { \ + fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \ + __LINE__, __FILE__, errno, strerror(errno)); \ + exit(1); \ + } while(0) + #define MAP_SIZE 4096UL #define MAP_MASK (MAP_SIZE - 1) int main(int argc, char **argv) { - int fd; - void *map_base, *virt_addr; + int fd; + void *map_base, *virt_addr; uint64_t read_result, writeval; + int do_write = 0; off_t target; int access_type = 'w'; - + if(argc < 2) { fprintf(stderr, "\nUsage:\t%s { address } [ type [ data ] ]\n" - "\taddress : memory address to act upon\n" - "\ttype : access operation type : [b]yte, [h]alfword, [w]ord, [d]oubleword\n" - "\tdata : data to be written\n\n", - argv[0]); + "\taddress : memory address to act upon\n" + "\ttype : access operation type : [b]yte, [h]alfword, [w]ord, [d]oubleword\n" + "\tdata : data to be written\n\n", + argv[0]); exit(1); } target = strtoull(argv[1], 0, 0); @@ -77,41 +82,44 @@ int main(int argc, char **argv) { if(argc > 2) access_type = tolower(argv[2][0]); + if (argc > 3) { + writeval = strtoul(argv[3], 0, 0); + do_write = 1; + } - if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL; - printf("/dev/mem opened.\n"); - fflush(stdout); - - /* Map one page */ - map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, target & ~MAP_MASK); - if(map_base == (void *) -1) FATAL; - printf("Memory mapped at address %p.\n", map_base); - fflush(stdout); - - virt_addr = map_base + (target & MAP_MASK); - switch(access_type) { - case 'b': - read_result = *((uint8_t *) virt_addr); - break; - case 'h': - read_result = *((uint16_t *) virt_addr); - break; - case 'w': - read_result = *((uint32_t *) virt_addr); - break; - case 'd': - read_result = *((uint64_t *) virt_addr); - break; - default: - fprintf(stderr, "Illegal data type '%c'.\n", access_type); - exit(2); - } - printf("Value at address 0x%X (%p): 0x%" PRIX64 "\n", target, virt_addr, read_result); - fflush(stdout); + if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) + FATAL; - if(argc > 3) { - writeval = strtoul(argv[3], 0, 0); + /* Map one page */ + map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, target & ~MAP_MASK); + if(map_base == (void *) -1) + FATAL; + + virt_addr = map_base + (target & MAP_MASK); + + if (!do_write) { + switch(access_type) { + case 'b': + read_result = *((uint8_t *) virt_addr); + break; + case 'h': + read_result = *((uint16_t *) virt_addr); + break; + case 'w': + read_result = *((uint32_t *) virt_addr); + break; + case 'd': + read_result = *((uint64_t *) virt_addr); + break; + default: + fprintf(stderr, "Illegal data type '%c'.\n", access_type); + exit(2); + } + + printf("0x%" PRIX64 "\n", read_result); + fflush(stdout); + } else { switch(access_type) { case 'b': *((uint8_t *) virt_addr) = writeval; @@ -129,12 +137,17 @@ int main(int argc, char **argv) { *((uint64_t *) virt_addr) = writeval; read_result = *((uint64_t *) virt_addr); break; + default: + fprintf(stderr, "Illegal data type '%c'.\n", access_type); + exit(2); } - printf("Written 0x%X; readback 0x%X\n", writeval, read_result); + printf("0x%" PRIX64 "\n", read_result); fflush(stdout); } - - if(munmap(map_base, MAP_SIZE) == -1) FATAL; - close(fd); - return 0; + + if(munmap(map_base, MAP_SIZE) == -1) + FATAL; + close(fd); + + return 0; } |