Attachment 45638 Details for Bug 34554 – C program for reading, writing, and manipulating contents of EDID EEPROMs attached to I2C/DDC interfaces using SMBus

C program for reading, writing, and manipulating contents of EDID EEPROMs attached to I2C/DDC interfaces using SMBus

edid-tool.c (text/plain), 7.78 KB, created by Andy Getz on 2011-04-14 15:40:19 UTC

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Creator: Andy Getz

Created: 2011-04-14 15:40:19 UTC

Size: 7.78 KB

patch

obsolete

>/* 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;
>}

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Attachments on bug 34554: 43640 | 43641 | 43642 | 43734 | 43735 | 43772 | 45143 | 45144 | 45145 | 45146 | 45147 | 45148 | 45638 | 45639

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