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/*
* Copyright (C) 2012 Samsung Electronics
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/stat.h>
#include <compiler.h>
#define CHECKSUM_OFFSET (14*1024-4)
#define FILE_PERM (S_IRUSR | S_IWUSR | S_IRGRP \
| S_IWGRP | S_IROTH | S_IWOTH)
/*
* Requirement for the fixed size SPL header:
* IROM code reads first (CHECKSUM_OFFSET + 4) bytes from boot device. It then
* calculates the checksum of CHECKSUM_OFFSET bytes and compares with data at
* CHECKSUM_OFFSET location.
*
* Requirement for the variable size SPL header:
* IROM code reads the below header to find out the size of the blob (total
* size, header size included) and its checksum. Then it reads the rest of the
* blob [i.e size - sizeof(struct var_size_header) bytes], calculates the
* checksum and compares it with value read from the header.
*/
struct var_size_header {
uint32_t spl_size;
uint32_t spl_checksum;
uint32_t reserved[2];
};
static const char *prog_name;
static void write_to_file(int ofd, void *buffer, int size)
{
if (write(ofd, buffer, size) == size)
return;
fprintf(stderr, "%s: Failed to write to output file: %s\n",
prog_name, strerror(errno));
exit(EXIT_FAILURE);
}
/*
* The argv is expected to include one optional parameter and two filenames:
* [--vs] IN OUT
*
* --vs - turns on the variable size SPL mode
* IN - the u-boot SPL binary, usually u-boot-spl.bin
* OUT - the prepared SPL blob, usually ${BOARD}-spl.bin
*
* This utility first reads the "u-boot-spl.bin" into a buffer. In case of
* fixed size SPL the buffer size is exactly CHECKSUM_OFFSET (such that
* smaller u-boot-spl.bin gets padded with 0xff bytes, the larger than limit
* u-boot-spl.bin causes an error). For variable size SPL the buffer size is
* eqaul to size of the IN file.
*
* Then it calculates checksum of the buffer by just summing up all bytes.
* Then
*
* - for fixed size SPL the buffer is written into the output file and the
* checksum is appended to the file in little endian format, which results
* in checksum added exactly at CHECKSUM_OFFSET.
*
* - for variable size SPL the checksum and file size are stored in the
* var_size_header structure (again, in little endian format) and the
* structure is written into the output file. Then the buffer is written
* into the output file.
*/
int main(int argc, char **argv)
{
unsigned char *buffer;
int i, ifd, ofd;
uint32_t checksum = 0;
off_t len;
int var_size_flag, read_size, count;
struct stat stat;
const int if_index = argc - 2; /* Input file name index in argv. */
const int of_index = argc - 1; /* Output file name index in argv. */
/* Strip path off the program name. */
prog_name = strrchr(argv[0], '/');
if (prog_name)
prog_name++;
else
prog_name = argv[0];
if ((argc < 3) ||
(argc > 4) ||
((argc == 4) && strcmp(argv[1], "--vs"))) {
fprintf(stderr, "Usage: %s [--vs] <infile> <outfile>\n",
prog_name);
exit(EXIT_FAILURE);
}
/* four args mean variable size SPL wrapper is required */
var_size_flag = (argc == 4);
ifd = open(argv[if_index], O_RDONLY);
if (ifd < 0) {
fprintf(stderr, "%s: Can't open %s: %s\n",
prog_name, argv[if_index], strerror(errno));
exit(EXIT_FAILURE);
}
ofd = open(argv[of_index], O_WRONLY | O_CREAT | O_TRUNC, FILE_PERM);
if (ofd < 0) {
fprintf(stderr, "%s: Can't open %s: %s\n",
prog_name, argv[of_index], strerror(errno));
exit(EXIT_FAILURE);
}
if (fstat(ifd, &stat)) {
fprintf(stderr, "%s: Unable to get size of %s: %s\n",
prog_name, argv[if_index], strerror(errno));
exit(EXIT_FAILURE);
}
len = stat.st_size;
if (var_size_flag) {
read_size = len;
count = len;
} else {
if (len > CHECKSUM_OFFSET) {
fprintf(stderr,
"%s: %s is too big (exceeds %d bytes)\n",
prog_name, argv[if_index], CHECKSUM_OFFSET);
exit(EXIT_FAILURE);
}
count = CHECKSUM_OFFSET;
read_size = len;
}
buffer = malloc(count);
if (!buffer) {
fprintf(stderr,
"%s: Failed to allocate %d bytes to store %s\n",
prog_name, count, argv[if_index]);
exit(EXIT_FAILURE);
}
if (read(ifd, buffer, read_size) != read_size) {
fprintf(stderr, "%s: Can't read %s: %s\n",
prog_name, argv[if_index], strerror(errno));
exit(EXIT_FAILURE);
}
/* Pad if needed with 0xff to make flashing faster. */
if (read_size < count)
memset((char *)buffer + read_size, 0xff, count - read_size);
for (i = 0, checksum = 0; i < count; i++)
checksum += buffer[i];
checksum = cpu_to_le32(checksum);
if (var_size_flag) {
/* Prepare and write out the variable size SPL header. */
struct var_size_header vsh;
uint32_t spl_size;
memset(&vsh, 0, sizeof(vsh));
memcpy(&vsh.spl_checksum, &checksum, sizeof(checksum));
spl_size = cpu_to_le32(count + sizeof(struct var_size_header));
memcpy(&vsh.spl_size, &spl_size, sizeof(spl_size));
write_to_file(ofd, &vsh, sizeof(vsh));
}
write_to_file(ofd, buffer, count);
/* For fixed size SPL checksum is appended in the end. */
if (!var_size_flag)
write_to_file(ofd, &checksum, sizeof(checksum));
close(ifd);
close(ofd);
free(buffer);
return EXIT_SUCCESS;
}
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