/* Copyright (C) 2011 Andy Getzendanner //
// Hereby licensed AS-IS to anyone who wants it //
// Responsibility and liability for unintended consequences including //
// hardware damage are hereby disclaimed; USE ONLY AT YOUR OWN RISK //
// Note: compile with at least -O due to inlined SMBus functions //
// Note: errors in i2c-dev.h likely result from using the kernel-internal //
// version of that file rather than the userspace-facing one from the //
// i2c-tools package, available from: //
// http://www.lm-sensors.org/wiki/I2CTools */
#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <linux/i2c-dev.h>
#define EDID_I2C_ADDR 0x50
#define EDID_BLKSIZE 128
#define iferror(COND, FUNC) _iferror(COND, FUNC, __LINE__)
#define ifwarn(COND, FUNC) _ifwarn(COND, FUNC, __LINE__)
#define sizeel(X) sizeof(*X)
#define numel(X) (sizeof(X)/sizeel(X))
const uint8_t EDID_HEADER[8] = {0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00};
int main(int argc, char *argv[], char *envp[]);
void usage(void) __attribute__ ((__noreturn__));
void _iferror(int cond, const char *func, int line);
void _ifwarn(int cond, const char *func, int line);
void fhexbuf(FILE *stream, const uint8_t *buf, size_t size);
uint8_t checksum(const uint8_t *buf, size_t size);
void checkedid(const uint8_t *edid, int fatal);
int main(int argc, char *argv[], char *envp[]) {
int quiet = 0;
int force = 0;
argv++; argc--;
if (argc < 1) usage();
if (!strcmp(argv[0], "-q")) {
quiet = 1;
argv++; argc--;
if (argc < 1) usage();
}
if (!strcmp(argv[0], "-f")) {
force = 1;
argv++; argc--;
if (argc < 1) usage();
}
int fd = open(argv[0], O_RDWR);
iferror(fd < 0, "open");
argv++; argc--;
int ret = ioctl(fd, I2C_SLAVE, (ptrdiff_t) EDID_I2C_ADDR);
iferror(ret == -1, "ioctl");
if (argc != 1) usage();
if (!strcmp(argv[0], "read")) {
uint8_t buf[EDID_BLKSIZE];
size_t addr = 0x00;
for (size_t addr = 0; addr < sizeof(buf); addr++) {
int32_t rb = i2c_smbus_read_byte_data(fd, (uint8_t) addr);
iferror(rb == -1, "i2c_smbus_read_byte_data");
buf[addr] = (uint8_t) rb;
}
if (!quiet) fhexbuf(stderr, buf, sizeof(buf));
checkedid(buf, 0);
size_t wbc = fwrite(buf, sizeel(buf), numel(buf), stdout);
iferror(ferror(stdout), "fwrite");
iferror(wbc < numel(buf), "fwrite");
return EXIT_SUCCESS;
} else if (!strcmp(argv[0], "write")) {
uint8_t buf[EDID_BLKSIZE];
size_t rbc = fread(buf, sizeel(buf), numel(buf), stdin);
iferror(ferror(stdin), "fread");
iferror(rbc < numel(buf), "fread");
if (!quiet) fhexbuf(stderr, buf, sizeof(buf));
checkedid(buf, !force);
for (size_t addr = 0; addr < sizeof(buf); addr++) {
int32_t smret = i2c_smbus_write_byte_data(fd, (uint8_t) addr,
buf[addr]);
iferror(smret == -1, "i2c_smbus_write_byte_data");
}
return EXIT_SUCCESS;
} else if (!strcmp(argv[0], "check")) {
uint8_t buf[EDID_BLKSIZE];
size_t rbc = fread(buf, sizeel(buf), numel(buf), stdin);
iferror(ferror(stdin), "fread");
iferror(rbc < numel(buf), "fread");
if (!quiet) fhexbuf(stderr, buf, sizeof(buf));
checkedid(buf, 1);
return EXIT_SUCCESS;
} else if (!strcmp(argv[0], "fix")) {
uint8_t buf[EDID_BLKSIZE];
size_t rbc = fread(buf, sizeel(buf), numel(buf), stdin);
iferror(ferror(stdin), "fread");
iferror(rbc < numel(buf), "fread");
if (!quiet) fhexbuf(stderr, buf, sizeof(buf));
int change = 0;
if (memcmp(buf, EDID_HEADER, sizeof(EDID_HEADER))) {
(void) fprintf(stderr, "INFO at %d: Fixing header\n", __LINE__);
(void) memcpy(buf, EDID_HEADER, sizeof(EDID_HEADER));
change = 1;
}
uint8_t cksum = 0x00 - checksum(buf, EDID_BLKSIZE - 1);
if (buf[EDID_BLKSIZE - 1] != cksum) {
(void) fprintf(stderr, "INFO at %d: Fixing checksum\n", __LINE__);
buf[EDID_BLKSIZE - 1] = cksum;
change = 1;
}
if (change && !quiet) fhexbuf(stderr, buf, sizeof(buf));
size_t wbc = fwrite(buf, sizeel(buf), numel(buf), stdout);
iferror(ferror(stdout), "fwrite");
iferror(wbc < numel(buf), "fwrite");
return EXIT_SUCCESS;
} else usage();
}
void usage(void) {
(void) fputs("Usage: edid-tool [-q] [-f] i2cdev read|write|tryfix\n"
" i2cdev - probably like /dev/i2c-%d\n"
" read - outputs a binary blob to stdout\n"
" write - reads a binary blob from stdin\n"
" check - reads a binary blob from stdin and checks its header and\n"
" checksum\n"
" fix - reads a binary blob from stdin, corrects the header and\n"
" checksum if necessary, and writes to stdout\n"
" -q - suppresses output of hex block to stderr\n"
" -f - ignores checksum and header errors when writing EDID checksum\n"
" argument order must be as specified above\n",
stderr);
exit(EXIT_FAILURE);
}
void _iferror(int cond, const char *func, int line) {
if (cond) {
(void) fprintf(stderr, "ERROR at %d: %s() failed: %s\n", line, func,
strerror(errno));
exit(EXIT_FAILURE);
} else return;
}
void _ifwarn(int cond, const char *func, int line) {
if (cond) (void) fprintf(stderr, "WARN at %d: %s() failed: %s\n", line,
func, strerror(errno));
return;
}
void fhexbuf(FILE *stream, const uint8_t *buf, size_t size) {
(void) fprintf(stream, " ");
for (int addr = 0; addr < 0x10; addr++)
(void) fprintf(stream, (addr % 0x04 == 0x03) ? "%2x " : "%2x ",
addr);
(void) fputc(' ', stream);
for (int addr = 0; addr < 0x10; addr++) {
(void) fprintf(stream, "%1x", addr);
if ((addr % 0x04 == 0x03) && (addr % 0x10 != 0x0f))
(void) fputc(' ', stream);
}
(void) fputc(' ', stream);
(void) fputc('\n', stream);
for (size_t rowaddr = 0; rowaddr < size; rowaddr += 0x10) {
(void) fprintf(stream, "%08zx ", rowaddr);
for (size_t addr = rowaddr;
(addr < rowaddr + 0x10) && (addr < size); addr++)
(void) fprintf(stream,
(addr % 0x04 == 0x03) ? "%02"PRIx8" " :
"%02"PRIx8" ",
buf[addr]);
for (size_t addr = size; addr < rowaddr + 0x10; addr++)
(void) fprintf(stream, (addr % 0x04 == 0x03) ? " " : " ",
buf[addr]);
(void) fputc('|', stream);
for (size_t addr = rowaddr;
(addr < rowaddr + 0x10) && (addr < size); addr++) {
(void) fputc(isprint(buf[addr]) ? buf[addr] : '.', stream);
if ((addr % 0x04 == 0x03) &&
(addr % 0x10 != 0x0f) &&
(addr < size - 1))
(void) fputc(' ', stream);
}
(void) fputc('|', stream);
(void) fputc('\n', stream);
}
return;
}
inline uint8_t checksum(const uint8_t *buf, size_t size) {
uint8_t sum = 0x00;
while (size--) sum += buf[size];
return sum;
}
void checkedid(const uint8_t *edid, int fatal) {
int bad = 0;
if (memcmp(edid, EDID_HEADER, sizeof(EDID_HEADER))) {
(void) fprintf(stderr, "%s at %d: Bad header: 0x"
"%02"PRIx8"%02"PRIx8" %02"PRIx8"%02"PRIx8" "
"%02"PRIx8"%02"PRIx8" %02"PRIx8"%02"PRIx8"\n",
fatal ? "ERROR" : "WARN", __LINE__,
edid[0], edid[1], edid[2], edid[3],
edid[4], edid[5], edid[6], edid[7]);
bad = 1;
}
uint8_t cksum = checksum(edid, EDID_BLKSIZE);
if (cksum) {
(void) fprintf(stderr, "%s at %d: Bad checksum: 0x%02"PRIx8"\n",
fatal ? "ERROR" : "WARN", __LINE__, cksum);
bad = 1;
}
if (fatal && bad) exit(EXIT_FAILURE);
else return;
}