From c37e7e56b14ce85e2097b416b5708d8ae096bb36 Mon Sep 17 00:00:00 2001
From: INAGAKI Hiroshi <musashino.open@gmail.com>
Date: Thu, 2 Jan 2025 14:23:36 +0900
Subject: [PATCH] nosimg-enc: add new tool for XikeStor SKS8300 series

Add a new tool to generate a encoded firmware image for XikeStor SKS8300
series devices.

In this format, only the first 512 bytes (0x200) are encoded with a
fixed patten (length: 0x100).

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>
---
 CMakeLists.txt   |   1 +
 src/nosimg-enc.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 src/nosimg-enc.c

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3352e26..71c604c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -95,6 +95,7 @@ FW_UTIL(motorola-bin "" "" "")
 FW_UTIL(nand_ecc "" "" "")
 FW_UTIL(nec-enc "" --std=gnu99 "")
 FW_UTIL(nec-usbatermfw "" -D_DEFAULT_SOURCE "")
+FW_UTIL(nosimg-enc "" --std=gnu99 "")
 FW_UTIL(osbridge-crc "" "" "")
 FW_UTIL(oseama src/md5.c "" "")
 FW_UTIL(otrx "" "" "")
diff --git a/src/nosimg-enc.c b/src/nosimg-enc.c
new file mode 100644
index 0000000..64f07e9
--- /dev/null
+++ b/src/nosimg-enc.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * nosimg-enc.c - encode/decode "nos.img" image for XikeStor SKS8300 series
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#define ENCODE_BLKLEN	0x100
+#define ENCODE_BLOCKS	2
+
+static uint32_t patterns[] = {
+	0xeeddcc21,  0x5355eecc,  0xdd55807e,  0x00000000,
+	0xcdbddfae,  0xbb9b8901,  0x70e5ccdd,  0xf6fc8364,
+	0xecddcef1,  0xe354fed0,  0xbdabdde1,  0xe4b4d583,
+	0xedfed0cd,  0xb655cca3,  0xedd5c67e,  0xddcc2153,
+	0xec4ddc00,  0x5355cdc3,  0x2201807e,  0xefbc7566,
+	0xa6c0cc2f,  0xfed0eecc,  0xdd550101,  0x0101c564,
+	0x9945ab32,  0x55807eef,  0x55807eef,  0xbc756689,
+	0xe31d83dd,  0xfe558eab,  0x7d55807e,  0xff01ac66,
+	0x0ec992d9,  0x73e50101,  0xbde510ce,  0x0101bae8,
+	0x3edd81a1,  0x53330101,  0x9ac510aa,  0x01ce8ae1,
+	0xb1fb0080,  0x53770000,  0x70dc0001,  0x0000cbb1,
+	0xa0300000,  0x55a60000,  0xcabd0101,  0x0000c9b2,
+	0x81900100,  0x5a210001,  0x79bc0100,  0x78007bb3,
+	0xd4970100,  0x5355a9fc,  0xdda501be,  0xafc175c5,
+	0x8ed77700,  0x55d00dac,  0x0155807e,  0xefbc7ee6,
+	0xf16c5200,  0x331698cc,  0x01010101,  0x00007988,
+};
+
+static void __attribute__((noreturn)) usage(void)
+{
+	fprintf(stderr, "Usage: nosimg-enc -i infile -o outfile [-d]\n");
+	exit(EXIT_FAILURE);
+}
+
+static void EncodeBlock100(uint8_t *data, bool decode)
+{
+	int i;
+
+	for (i = 0; i < ENCODE_BLKLEN; i++)
+	{
+		uint32_t tmp;
+		tmp = patterns[i / sizeof(uint32_t)];
+		tmp >>= (sizeof(uint32_t) - i % sizeof(uint32_t) - 1) * 8;
+		data[i] -= (tmp & 0xff) * (decode ? -1 : 1);
+	}
+}
+
+int main(int argc, char **argv)
+{
+	int i, c, n, ret = EXIT_SUCCESS;
+	char *ifn = NULL, *ofn = NULL;
+	bool decode = false;
+	uint8_t buf[0x10000];
+	FILE *out, *in;
+
+	while ((c = getopt(argc, argv, "i:o:dh")) != -1) {
+		switch (c) {
+		case 'i':
+			ifn = optarg;
+			break;
+		case 'o':
+			ofn = optarg;
+			break;
+		case 'd':
+			decode = true;
+			break;
+		case 'h':
+		default:
+			usage();
+		}
+	}
+
+	if (optind != argc || optind == 1) {
+		fprintf(stderr, "illegal arg \"%s\"\n", argv[optind]);
+		usage();
+	}
+
+	in = fopen(ifn, "r");
+	if (!in) {
+		perror("can not open input file");
+		usage();
+	}
+
+	out = fopen(ofn, "w");
+	if (!out) {
+		perror("can not open output file");
+		usage();
+	}
+
+	/* encode/decode the first 512 bytes (0x100 x2) */
+	for (i = 0; i < ENCODE_BLOCKS; i++) {
+		n = fread(buf, 1, ENCODE_BLKLEN, in);
+		if (n < ENCODE_BLKLEN) {
+			perror("failed to read data for encoding/decoding\n");
+			ret = EXIT_FAILURE;
+			goto out;
+		}
+
+		EncodeBlock100(buf, decode);
+		fwrite(buf, 1, n, out);
+	}
+
+	/* copy the remaining data */
+	while ((n = fread(buf, 1, sizeof(buf), in)) > 0) {
+		if (fwrite(buf, 1, n, out) != n) {
+			perror("failed to write");
+			ret = EXIT_FAILURE;
+			goto out;
+		}
+	}
+
+	if (ferror(in)) {
+		perror("failed to read");
+		ret = EXIT_FAILURE;
+	}
+
+out:
+	fclose(in);
+	fclose(out);
+	return ret;
+}