/* * flash_otp_write.c -- write One-Time-Program data */ #include <stdio.h> #include <unistd.h> #include <fcntl.h> #include <string.h> #include <stdlib.h> #include <errno.h> #include <sys/types.h> #include <sys/ioctl.h> #include <mtd/mtd-user.h> int main(int argc,char *argv[]) { int fd, val, ret, size, wrote, len; mtd_info_t mtdInfo; off_t offset; char *p, buf[2048]; if (argc != 4 || strcmp(argv[1], "-u")) { fprintf(stderr, "Usage: %s -u <device> <offset>\n", argv[0]); fprintf(stderr, "the raw data to write should be provided on stdin\n"); fprintf(stderr, "CAUTION! ONCE SET TO 0, OTP DATA BITS CAN'T BE ERASED!\n"); return EINVAL; } fd = open(argv[2], O_WRONLY); if (fd < 0) { perror(argv[2]); return errno; } val = MTD_OTP_USER; ret = ioctl(fd, OTPSELECT, &val); if (ret < 0) { perror("OTPSELECT"); return errno; } if (ioctl(fd, MEMGETINFO, &mtdInfo)) { perror("MEMGETINFO"); return errno; } offset = strtoul(argv[3], &p, 0); if (argv[3][0] == 0 || *p != 0) { fprintf(stderr, "%s: bad offset value\n", argv[0]); return ERANGE; } if (lseek(fd, offset, SEEK_SET) == (off_t)-1) { perror("lseek()"); return errno; } printf("Writing OTP user data on %s at offset 0x%lx\n", argv[2], offset); if (mtdInfo.type == MTD_NANDFLASH) len = mtdInfo.writesize; else len = 256; wrote = 0; while ((size = read(0, buf, len))) { if (size < 0) { perror("read()"); return errno; } p = buf; while (size > 0) { if (mtdInfo.type == MTD_NANDFLASH) { /* Fill remain buffers with 0xff */ memset(buf + size, 0xff, mtdInfo.writesize - size); size = mtdInfo.writesize; } ret = write(fd, p, size); if (ret < 0) { perror("write()"); return errno; } if (ret == 0) { printf("write() returned 0 after writing %d bytes\n", wrote); return 0; } p += ret; wrote += ret; size -= ret; } } printf("Wrote %d bytes of OTP user data\n", wrote); return 0; }