| /* |
| * devmem2.c: Simple program to read/write from/to any location in memory. |
| * |
| * Copyright (C) 2000, Jan-Derk Bakker (jdb@lartmaker.nl) |
| * |
| * |
| * This software has been developed for the LART computing board |
| * (http://www.lart.tudelft.nl/). The development has been sponsored by |
| * the Mobile MultiMedia Communications (http://www.mmc.tudelft.nl/) |
| * and Ubiquitous Communications (http://www.ubicom.tudelft.nl/) |
| * projects. |
| * |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| * |
| */ |
| |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <errno.h> |
| #include <signal.h> |
| #include <fcntl.h> |
| #include <ctype.h> |
| #include <termios.h> |
| #include <sys/types.h> |
| #include <sys/mman.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 MAP_SIZE 4096UL |
| #define MAP_MASK (MAP_SIZE - 1) |
| |
| int main(int argc, char **argv) { |
| int fd; |
| void *map_base, *virt_addr; |
| unsigned long read_result, writeval; |
| 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\n" |
| "\tdata : data to be written\n\n", |
| argv[0]); |
| exit(1); |
| } |
| target = strtoul(argv[1], 0, 0); |
| |
| if(argc > 2) |
| access_type = tolower(argv[2][0]); |
| |
| |
| 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 = *((unsigned char *) virt_addr); |
| break; |
| case 'h': |
| read_result = *((unsigned short *) virt_addr); |
| break; |
| case 'w': |
| read_result = *((unsigned long *) virt_addr); |
| break; |
| default: |
| fprintf(stderr, "Illegal data type '%c'.\n", access_type); |
| exit(2); |
| } |
| printf("Value at address 0x%X (%p): 0x%X\n", target, virt_addr, read_result); |
| fflush(stdout); |
| |
| if(argc > 3) { |
| writeval = strtoul(argv[3], 0, 0); |
| switch(access_type) { |
| case 'b': |
| *((unsigned char *) virt_addr) = writeval; |
| read_result = *((unsigned char *) virt_addr); |
| break; |
| case 'h': |
| *((unsigned short *) virt_addr) = writeval; |
| read_result = *((unsigned short *) virt_addr); |
| break; |
| case 'w': |
| *((unsigned long *) virt_addr) = writeval; |
| read_result = *((unsigned long *) virt_addr); |
| break; |
| } |
| printf("Written 0x%X; readback 0x%X\n", writeval, read_result); |
| fflush(stdout); |
| } |
| |
| if(munmap(map_base, MAP_SIZE) == -1) FATAL; |
| close(fd); |
| return 0; |
| } |
| |