1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2012 Samsung Electronics
4 */
5
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <unistd.h>
9 #include <fcntl.h>
10 #include <errno.h>
11 #include <string.h>
12 #include <sys/stat.h>
13 #include <compiler.h>
14
15 #define CHECKSUM_OFFSET (14*1024-4)
16 #define FILE_PERM (S_IRUSR | S_IWUSR | S_IRGRP \
17 | S_IWGRP | S_IROTH | S_IWOTH)
18 /*
19 * Requirement for the fixed size SPL header:
20 * IROM code reads first (CHECKSUM_OFFSET + 4) bytes from boot device. It then
21 * calculates the checksum of CHECKSUM_OFFSET bytes and compares with data at
22 * CHECKSUM_OFFSET location.
23 *
24 * Requirement for the variable size SPL header:
25
26 * IROM code reads the below header to find out the size of the blob (total
27 * size, header size included) and its checksum. Then it reads the rest of the
28 * blob [i.e size - sizeof(struct var_size_header) bytes], calculates the
29 * checksum and compares it with value read from the header.
30 */
31 struct var_size_header {
32 uint32_t spl_size;
33 uint32_t spl_checksum;
34 uint32_t reserved[2];
35 };
36
37 static const char *prog_name;
38
write_to_file(int ofd,void * buffer,int size)39 static void write_to_file(int ofd, void *buffer, int size)
40 {
41 if (write(ofd, buffer, size) == size)
42 return;
43
44 fprintf(stderr, "%s: Failed to write to output file: %s\n",
45 prog_name, strerror(errno));
46 exit(EXIT_FAILURE);
47 }
48
49 /*
50 * The argv is expected to include one optional parameter and two filenames:
51 * [--vs] IN OUT
52 *
53 * --vs - turns on the variable size SPL mode
54 * IN - the u-boot SPL binary, usually u-boot-spl.bin
55 * OUT - the prepared SPL blob, usually ${BOARD}-spl.bin
56 *
57 * This utility first reads the "u-boot-spl.bin" into a buffer. In case of
58 * fixed size SPL the buffer size is exactly CHECKSUM_OFFSET (such that
59 * smaller u-boot-spl.bin gets padded with 0xff bytes, the larger than limit
60 * u-boot-spl.bin causes an error). For variable size SPL the buffer size is
61 * eqaul to size of the IN file.
62 *
63 * Then it calculates checksum of the buffer by just summing up all bytes.
64 * Then
65 *
66 * - for fixed size SPL the buffer is written into the output file and the
67 * checksum is appended to the file in little endian format, which results
68 * in checksum added exactly at CHECKSUM_OFFSET.
69 *
70 * - for variable size SPL the checksum and file size are stored in the
71 * var_size_header structure (again, in little endian format) and the
72 * structure is written into the output file. Then the buffer is written
73 * into the output file.
74 */
main(int argc,char ** argv)75 int main(int argc, char **argv)
76 {
77 unsigned char *buffer;
78 int i, ifd, ofd;
79 uint32_t checksum = 0;
80 off_t len;
81 int var_size_flag, read_size, count;
82 struct stat stat;
83 const int if_index = argc - 2; /* Input file name index in argv. */
84 const int of_index = argc - 1; /* Output file name index in argv. */
85
86 /* Strip path off the program name. */
87 prog_name = strrchr(argv[0], '/');
88 if (prog_name)
89 prog_name++;
90 else
91 prog_name = argv[0];
92
93 if ((argc < 3) ||
94 (argc > 4) ||
95 ((argc == 4) && strcmp(argv[1], "--vs"))) {
96 fprintf(stderr, "Usage: %s [--vs] <infile> <outfile>\n",
97 prog_name);
98 exit(EXIT_FAILURE);
99 }
100
101 /* four args mean variable size SPL wrapper is required */
102 var_size_flag = (argc == 4);
103
104 ifd = open(argv[if_index], O_RDONLY);
105 if (ifd < 0) {
106 fprintf(stderr, "%s: Can't open %s: %s\n",
107 prog_name, argv[if_index], strerror(errno));
108 exit(EXIT_FAILURE);
109 }
110
111 ofd = open(argv[of_index], O_WRONLY | O_CREAT | O_TRUNC, FILE_PERM);
112 if (ofd < 0) {
113 fprintf(stderr, "%s: Can't open %s: %s\n",
114 prog_name, argv[of_index], strerror(errno));
115 exit(EXIT_FAILURE);
116 }
117
118 if (fstat(ifd, &stat)) {
119 fprintf(stderr, "%s: Unable to get size of %s: %s\n",
120 prog_name, argv[if_index], strerror(errno));
121 exit(EXIT_FAILURE);
122 }
123
124 len = stat.st_size;
125
126 if (var_size_flag) {
127 read_size = len;
128 count = len;
129 } else {
130 if (len > CHECKSUM_OFFSET) {
131 fprintf(stderr,
132 "%s: %s is too big (exceeds %d bytes)\n",
133 prog_name, argv[if_index], CHECKSUM_OFFSET);
134 exit(EXIT_FAILURE);
135 }
136 count = CHECKSUM_OFFSET;
137 read_size = len;
138 }
139
140 buffer = malloc(count);
141 if (!buffer) {
142 fprintf(stderr,
143 "%s: Failed to allocate %d bytes to store %s\n",
144 prog_name, count, argv[if_index]);
145 exit(EXIT_FAILURE);
146 }
147
148 if (read(ifd, buffer, read_size) != read_size) {
149 fprintf(stderr, "%s: Can't read %s: %s\n",
150 prog_name, argv[if_index], strerror(errno));
151 exit(EXIT_FAILURE);
152 }
153
154 /* Pad if needed with 0xff to make flashing faster. */
155 if (read_size < count)
156 memset((char *)buffer + read_size, 0xff, count - read_size);
157
158 for (i = 0, checksum = 0; i < count; i++)
159 checksum += buffer[i];
160 checksum = cpu_to_le32(checksum);
161
162 if (var_size_flag) {
163 /* Prepare and write out the variable size SPL header. */
164 struct var_size_header vsh;
165 uint32_t spl_size;
166
167 memset(&vsh, 0, sizeof(vsh));
168 memcpy(&vsh.spl_checksum, &checksum, sizeof(checksum));
169
170 spl_size = cpu_to_le32(count + sizeof(struct var_size_header));
171 memcpy(&vsh.spl_size, &spl_size, sizeof(spl_size));
172 write_to_file(ofd, &vsh, sizeof(vsh));
173 }
174
175 write_to_file(ofd, buffer, count);
176
177 /* For fixed size SPL checksum is appended in the end. */
178 if (!var_size_flag)
179 write_to_file(ofd, &checksum, sizeof(checksum));
180
181 close(ifd);
182 close(ofd);
183 free(buffer);
184
185 return EXIT_SUCCESS;
186 }
187