1 files changed, 96 insertions, 0 deletions
diff --git a/flash_otp_write.c b/flash_otp_write.c
new file mode 100644
index 0000000..71d3168
--- /dev/null
+++ b/flash_otp_write.c
@@ -0,0 +1,96 @@
+/*
+ * 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.oobblock;
+	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.oobblock - size);
+				size = mtdInfo.oobblock;
+			}
+			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;
+}