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/*
This program is hereby placed into the public domain.
Of course the program is provided without warranty of any kind.
*/
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>
#include "i2c-dev.h"
/*
this program can read 24C16 (and probably smaller ones, too)
I wrote it as a quick and dirty hack because my satellite receiver
hung again... so I had to reprogram the eeprom where is stores it's
settings.
*/
#define DEFAULT_I2C_BUS "/dev/i2c-0"
#define DEFAULT_EEPROM_ADDR 0x50 /* the 24C16 sits on i2c address 0x50 */
#define DEFAULT_NUM_PAGES 8 /* we default to a 24C16 eeprom which has 8 pages */
#define BYTES_PER_PAGE 256 /* one eeprom page is 256 byte */
#define MAX_BYTES 8 /* max number of bytes to write in one chunk */
/* ... note: 24C02 and 24C01 only allow 8 bytes to be written in one chunk. *
* if you are going to write 24C04,8,16 you can change this to 16 */
/* write len bytes (stored in buf) to eeprom at address addr, page-offset offset */
/* if len=0 (buf may be NULL in this case) you can reposition the eeprom's read-pointer */
/* return 0 on success, -1 on failure */
int eeprom_write(int fd,
unsigned int addr,
unsigned int offset,
unsigned char *buf,
unsigned char len
){
struct i2c_rdwr_ioctl_data msg_rdwr;
struct i2c_msg i2cmsg;
int i;
char _buf[MAX_BYTES + 1];
if(len>MAX_BYTES){
fprintf(stderr,"I can only write MAX_BYTES bytes at a time!\n");
return -1;
}
if(len+offset >256){
fprintf(stderr,"Sorry, len(%d)+offset(%d) > 256 (page boundary)\n",
len,offset);
return -1;
}
_buf[0]=offset; /* _buf[0] is the offset into the eeprom page! */
for(i=0;i<len;i++) /* copy buf[0..n] -> _buf[1..n+1] */
_buf[1+i]=buf[i];
msg_rdwr.msgs = &i2cmsg;
msg_rdwr.nmsgs = 1;
i2cmsg.addr = addr;
i2cmsg.flags = 0;
i2cmsg.len = 1+len;
i2cmsg.buf = _buf;
if((i=ioctl(fd,I2C_RDWR,&msg_rdwr))<0){
perror("ioctl()");
fprintf(stderr,"ioctl returned %d\n",i);
return -1;
}
if(len>0)
fprintf(stderr,"Wrote %d bytes to eeprom at 0x%02x, offset %08x\n",
len,addr,offset);
else
fprintf(stderr,"Positioned pointer in eeprom at 0x%02x to offset %08x\n",
addr,offset);
return 0;
}
/* read len bytes stored in eeprom at address addr, offset offset in array buf */
/* return -1 on error, 0 on success */
int eeprom_read(int fd,
unsigned int addr,
unsigned int offset,
unsigned char *buf,
unsigned char len
){
struct i2c_rdwr_ioctl_data msg_rdwr;
struct i2c_msg i2cmsg;
int i;
if(len>MAX_BYTES){
fprintf(stderr,"I can only write MAX_BYTES bytes at a time!\n");
return -1;
}
if(eeprom_write(fd,addr,offset,NULL,0)<0)
return -1;
msg_rdwr.msgs = &i2cmsg;
msg_rdwr.nmsgs = 1;
i2cmsg.addr = addr;
i2cmsg.flags = I2C_M_RD;
i2cmsg.len = len;
i2cmsg.buf = buf;
if((i=ioctl(fd,I2C_RDWR,&msg_rdwr))<0){
perror("ioctl()");
fprintf(stderr,"ioctl returned %d\n",i);
return -1;
}
fprintf(stderr,"Read %d bytes from eeprom at 0x%02x, offset %08x\n",
len,addr,offset);
return 0;
}
int main(int argc, char **argv){
int i,j;
/* filedescriptor and name of device */
int d;
char *dn=DEFAULT_I2C_BUS;
/* filedescriptor and name of data file */
int f=-1;
char *fn=NULL;
unsigned int addr=DEFAULT_EEPROM_ADDR;
int rwmode=0;
int pages=DEFAULT_NUM_PAGES;
int force=0; /* suppress warning on write! */
while((i=getopt(argc,argv,"d:a:p:wyf:h"))>=0){
switch(i){
case 'h':
fprintf(stderr,"%s [-d dev] [-a adr] [-p pgs] [-w] [-y] [-f file]\n",argv[0]);
fprintf(stderr,"\tdev: device, e.g. /dev/i2c-0 (def)\n");
fprintf(stderr,"\tadr: base address of eeprom, eg 0xA0 (def)\n");
fprintf(stderr,"\tpgs: number of pages to read, eg 8 (def)\n");
fprintf(stderr,"\t-w : write to eeprom (default is reading!)\n");
fprintf(stderr,"\t-y : suppress warning when writing (default is to warn!)\n");
fprintf(stderr,"\t-f file: copy eeprom contents to/from file\n");
fprintf(stderr,"\t (default for read is test only; for write is all zeros)\n");
fprintf(stderr,"Note on pages/addresses:\n");
fprintf(stderr,"\teeproms with more than 256 byte appear as if they\n");
fprintf(stderr,"\twere several eeproms with consecutive addresses on the bus\n");
fprintf(stderr,"\tso we might as well address several seperate eeproms with\n");
fprintf(stderr,"\tincreasing addresses....\n\n");
exit(1);
break;
case 'd':
dn=optarg;
break;
case 'a':
if(sscanf(optarg,"0x%x",&addr)!=1){
fprintf(stderr,"Cannot parse '%s' as addrs., example: 0xa0\n",
optarg);
exit(1);
}
break;
case 'p':
if(sscanf(optarg,"%d",&pages)!=1){
fprintf(stderr,"Cannot parse '%s' as number of pages, example: 8\n",
optarg);
exit(1);
}
break;
case 'w':
rwmode++;
break;
case 'f':
fn=optarg;
break;
case 'y':
force++;
break;
}
}
fprintf(stderr,"base-address of eeproms : 0x%02x\n",addr);
fprintf(stderr,"number of pages to read : %d (0x%02x .. 0x%02x)\n",
pages,addr,addr+pages-1);
if(fn){
if(!rwmode) /* if we are reading, *WRITE* to file */
f=open(fn,O_WRONLY|O_CREAT,0666);
else /* if we are writing to eeprom, *READ* from file */
f=open(fn,O_RDONLY);
if(f<0){
fprintf(stderr,"Could not open data-file %s for reading or writing\n",fn);
perror(fn);
exit(1);
}
fprintf(stderr,"file opened for %7s : %s\n",rwmode?"reading":"writing",fn);
fprintf(stderr," on filedescriptor : %d\n",f);
}
if((d=open(dn,O_RDWR))<0){
fprintf(stderr,"Could not open i2c at %s\n",dn);
perror(dn);
exit(1);
}
fprintf(stderr,"i2c-devicenode is : %s\n",dn);
fprintf(stderr," on filedescriptor : %d\n\n",d);
/***
*** I'm not the one to blame of you screw your computer!
***/
if(rwmode & ! force){
unsigned char warnbuf[4];
fprintf(stderr,"**WARNING**\n");
fprintf(stderr," - \tYou have chosen to WRITE to this eeprom.\n");
fprintf(stderr,"\tMake sure that this tiny chip is *NOT* vital to the\n");
fprintf(stderr,"\toperation of your computer as you can easily corrupt\n");
fprintf(stderr,"\tthe configuration memory of your SDRAM-memory-module,\n");
fprintf(stderr,"\tyour IBM ThinkPad or whatnot...! Fixing these errors can be\n");
fprintf(stderr,"\ta time-consuming and very costly process!\n\n");
fprintf(stderr,"Things to consider:\n");
fprintf(stderr," - \tYou can have more than one i2c-bus, check in /proc/bus/i2c\n");
fprintf(stderr,"\tand specify the correct one with -d\n");
fprintf(stderr,"\tright now you have chosen to use '%s'\n",dn);
fprintf(stderr," - \tA eeprom can occupy several i2c-addresses (one per page)\n");
fprintf(stderr,"\tso please make sure that there is no vital eeprom in your computer\n");
fprintf(stderr,"\tsitting at addresses between 0x%02x and 0x%02x\n",addr,addr+pages-1);
fprintf(stderr,"Enter 'yes' to continue:");
fflush(stderr);
if(!fgets(warnbuf,sizeof(warnbuf),stdin)){
fprintf(stderr,"\nCould not read confirmation from stdin!\n");
exit(1);
}
if(strncmp(warnbuf,"yes",3)){
fprintf(stderr,"\n** ABORTING WRITE! **, you did not answer 'yes'\n");
exit(1);
}
}
for(i=0;i<pages;i++){
unsigned char buf[BYTES_PER_PAGE];
if(rwmode){
if(f>=0){
j=read(f,buf,sizeof(buf));
if(j<0){
fprintf(stderr,"Cannot read from file '%s'\n",fn);
perror(fn);
exit(1);
}
if(j!=sizeof(buf)){
fprintf(stderr,"File '%s' is too small, padding eeprom with zeroes\n",fn);
while(j<sizeof(buf))
buf[j++]=0;
}
} else {
for(j=0;j<sizeof(buf);j++)
buf[j]=0;
}
for(j=0;j<(BYTES_PER_PAGE/MAX_BYTES);j++)
if(eeprom_write(d,addr+i,j*MAX_BYTES,buf+(j*MAX_BYTES),MAX_BYTES)<0)
exit(1);
} else {
for(j=0;j<(BYTES_PER_PAGE/MAX_BYTES);j++)
if(eeprom_read(d,addr+i,j*MAX_BYTES,buf+(j*MAX_BYTES),MAX_BYTES)<0)
exit(1);
}
if(!rwmode && f>=0){
j=write(f,buf,sizeof(buf));
if(j!=sizeof(buf)){
fprintf(stderr,"Cannot write to file '%s'\n",fn);
perror(fn);
exit(1);
}
}
}
if(f>=0)
close(f);
close(d);
exit(0);
}
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