[packages] add devmem2
[openwrt/svn-archive/archive.git] / utils / devmem2 / src / devmem2.c
1 /*
2 * devmem2.c: Simple program to read/write from/to any location in memory.
3 *
4 * Copyright (C) 2000, Jan-Derk Bakker (J.D.Bakker@its.tudelft.nl)
5 *
6 *
7 * This software has been developed for the LART computing board
8 * (http://www.lart.tudelft.nl/). The development has been sponsored by
9 * the Mobile MultiMedia Communications (http://www.mmc.tudelft.nl/)
10 * and Ubiquitous Communications (http://www.ubicom.tudelft.nl/)
11 * projects.
12 *
13 * The author can be reached at:
14 *
15 * Jan-Derk Bakker
16 * Information and Communication Theory Group
17 * Faculty of Information Technology and Systems
18 * Delft University of Technology
19 * P.O. Box 5031
20 * 2600 GA Delft
21 * The Netherlands
22 *
23 *
24 * This program is free software; you can redistribute it and/or modify
25 * it under the terms of the GNU General Public License as published by
26 * the Free Software Foundation; either version 2 of the License, or
27 * (at your option) any later version.
28 *
29 * This program is distributed in the hope that it will be useful,
30 * but WITHOUT ANY WARRANTY; without even the implied warranty of
31 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
32 * GNU General Public License for more details.
33 *
34 * You should have received a copy of the GNU General Public License
35 * along with this program; if not, write to the Free Software
36 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
37 *
38 */
39
40 #include <stdio.h>
41 #include <stdlib.h>
42 #include <unistd.h>
43 #include <string.h>
44 #include <errno.h>
45 #include <signal.h>
46 #include <fcntl.h>
47 #include <ctype.h>
48 #include <termios.h>
49 #include <sys/types.h>
50 #include <sys/mman.h>
51
52 #define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \
53 __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0)
54
55 #define MAP_SIZE 4096UL
56 #define MAP_MASK (MAP_SIZE - 1)
57
58 int main(int argc, char **argv) {
59 int fd;
60 void *map_base, *virt_addr;
61 unsigned long read_result, writeval;
62 off_t target;
63 int access_type = 'w';
64
65 if(argc < 2) {
66 fprintf(stderr, "\nUsage:\t%s { address } [ type [ data ] ]\n"
67 "\taddress : memory address to act upon\n"
68 "\ttype : access operation type : [b]yte, [h]alfword, [w]ord\n"
69 "\tdata : data to be written\n\n",
70 argv[0]);
71 exit(1);
72 }
73 target = strtoul(argv[1], 0, 0);
74
75 if(argc > 2)
76 access_type = tolower(argv[2][0]);
77
78
79 if((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL;
80 printf("/dev/mem opened.\n");
81 fflush(stdout);
82
83 /* Map one page */
84 map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, target & ~MAP_MASK);
85 if(map_base == (void *) -1) FATAL;
86 printf("Memory mapped at address %p.\n", map_base);
87 fflush(stdout);
88
89 virt_addr = map_base + (target & MAP_MASK);
90 switch(access_type) {
91 case 'b':
92 read_result = *((unsigned char *) virt_addr);
93 break;
94 case 'h':
95 read_result = *((unsigned short *) virt_addr);
96 break;
97 case 'w':
98 read_result = *((unsigned long *) virt_addr);
99 break;
100 default:
101 fprintf(stderr, "Illegal data type '%c'.\n", access_type);
102 exit(2);
103 }
104 printf("Value at address 0x%lX (%p): 0x%lX\n", target, virt_addr, read_result);
105 fflush(stdout);
106
107 if(argc > 3) {
108 writeval = strtoul(argv[3], 0, 0);
109 switch(access_type) {
110 case 'b':
111 *((unsigned char *) virt_addr) = writeval;
112 read_result = *((unsigned char *) virt_addr);
113 break;
114 case 'h':
115 *((unsigned short *) virt_addr) = writeval;
116 read_result = *((unsigned short *) virt_addr);
117 break;
118 case 'w':
119 *((unsigned long *) virt_addr) = writeval;
120 read_result = *((unsigned long *) virt_addr);
121 break;
122 }
123 printf("Written 0x%lX; readback 0x%lX\n", writeval, read_result);
124 fflush(stdout);
125 }
126
127 if(munmap(map_base, MAP_SIZE) == -1) FATAL;
128 close(fd);
129 return 0;
130 }
131
132