1 /*
2  * Copyright (C) 2011 Samsung Electronics
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <unistd.h>
10 #include <fcntl.h>
11 #include <errno.h>
12 #include <string.h>
13 #include <sys/stat.h>
14 
15 #define CHECKSUM_OFFSET		(14*1024-4)
16 #define BUFSIZE			(16*1024)
17 #define FILE_PERM		(S_IRUSR | S_IWUSR | S_IRGRP \
18 				| S_IWGRP | S_IROTH | S_IWOTH)
19 /*
20 * Requirement:
21 * IROM code reads first 14K bytes from boot device.
22 * It then calculates the checksum of 14K-4 bytes and compare with data at
23 * 14K-4 offset.
24 *
25 * This function takes two filenames:
26 * IN  "u-boot-spl.bin" and
27 * OUT "u-boot-mmc-spl.bin" as filenames.
28 * It reads the "u-boot-spl.bin" in 16K buffer.
29 * It calculates checksum of 14K-4 Bytes and stores at 14K-4 offset in buffer.
30 * It writes the buffer to "u-boot-mmc-spl.bin" file.
31 */
32 
33 int main(int argc, char **argv)
34 {
35 	int i, len;
36 	unsigned char buffer[BUFSIZE] = {0};
37 	int ifd, ofd;
38 	unsigned int checksum = 0, count;
39 
40 	if (argc != 3) {
41 		printf(" %d Wrong number of arguments\n", argc);
42 		exit(EXIT_FAILURE);
43 	}
44 
45 	ifd = open(argv[1], O_RDONLY);
46 	if (ifd < 0) {
47 		fprintf(stderr, "%s: Can't open %s: %s\n",
48 			argv[0], argv[1], strerror(errno));
49 		exit(EXIT_FAILURE);
50 	}
51 
52 	ofd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, FILE_PERM);
53 	if (ofd < 0) {
54 		fprintf(stderr, "%s: Can't open %s: %s\n",
55 			argv[0], argv[2], strerror(errno));
56 		if (ifd)
57 			close(ifd);
58 		exit(EXIT_FAILURE);
59 	}
60 
61 	len = lseek(ifd, 0, SEEK_END);
62 	lseek(ifd, 0, SEEK_SET);
63 
64 	count = (len < CHECKSUM_OFFSET) ? len : CHECKSUM_OFFSET;
65 
66 	if (read(ifd, buffer, count) != count) {
67 		fprintf(stderr, "%s: Can't read %s: %s\n",
68 			argv[0], argv[1], strerror(errno));
69 
70 		if (ifd)
71 			close(ifd);
72 		if (ofd)
73 			close(ofd);
74 
75 		exit(EXIT_FAILURE);
76 	}
77 
78 	for (i = 0, checksum = 0; i < CHECKSUM_OFFSET; i++)
79 		checksum += buffer[i];
80 
81 	memcpy(&buffer[CHECKSUM_OFFSET], &checksum, sizeof(checksum));
82 
83 	if (write(ofd, buffer, BUFSIZE) != BUFSIZE) {
84 		fprintf(stderr, "%s: Can't write %s: %s\n",
85 			argv[0], argv[2], strerror(errno));
86 
87 		if (ifd)
88 			close(ifd);
89 		if (ofd)
90 			close(ofd);
91 
92 		exit(EXIT_FAILURE);
93 	}
94 
95 	if (ifd)
96 		close(ifd);
97 	if (ofd)
98 		close(ofd);
99 
100 	return EXIT_SUCCESS;
101 }
102