1/*
2 * Makes a Motorola PPCBUG ROM bootable image which can be flashed
3 * into one of the FLASH banks on a Motorola PowerPlus board.
4 *
5 * Author: Matt Porter <mporter@mvista.com>
6 *
7 * 2001 (c) MontaVista, Software, Inc.  This file is licensed under
8 * the terms of the GNU General Public License version 2.  This program
9 * is licensed "as is" without any warranty of any kind, whether express
10 * or implied.
11 */
12
13#define ELF_HEADER_SIZE	65536
14
15#include <unistd.h>
16#include <sys/stat.h>
17#include <string.h>
18#include <stdio.h>
19#include <stdlib.h>
20#include <errno.h>
21#include <fcntl.h>
22#include <netinet/in.h>
23#ifdef __sun__
24#include <inttypes.h>
25#else
26#include <stdint.h>
27#endif
28
29/* size of read buffer */
30#define SIZE 0x1000
31
32/* PPCBUG ROM boot header */
33typedef struct bug_boot_header {
34  uint8_t	magic_word[4];		/* "BOOT" */
35  uint32_t	entry_offset;		/* Offset from top of header to code */
36  uint32_t	routine_length;		/* Length of code */
37  uint8_t	routine_name[8];	/* Name of the boot code */
38} bug_boot_header_t;
39
40#define HEADER_SIZE	sizeof(bug_boot_header_t)
41
42void update_checksum(void *buf, size_t size, uint16_t *sum)
43{
44	uint32_t csum = *sum;
45
46	while (size) {
47		csum += *(uint16_t *)buf;
48		if (csum > 0xffff)
49			csum -= 0xffff;
50		buf = (uint16_t *)buf + 1;
51		size -= 2;
52	}
53	*sum = csum;
54}
55
56uint32_t copy_image(int in_fd, int out_fd, uint16_t *sum)
57{
58	uint8_t buf[SIZE];
59	int offset = 0;
60	int n;
61	uint32_t image_size = 0;
62
63	lseek(in_fd, ELF_HEADER_SIZE, SEEK_SET);
64
65	/* Copy an image while recording its size */
66	while ( (n = read(in_fd, buf + offset, SIZE - offset)) > 0 ) {
67		n += offset;
68		offset = n & 1;
69		n -= offset;
70		image_size = image_size + n;
71		/* who's going to deal with short writes? */
72		write(out_fd, buf, n);
73		update_checksum(buf, n, sum);
74		if (offset)
75			buf[0] = buf[n];
76	}
77
78	/* BUG romboot requires that our size is divisible by 2 */
79	/* align image to 2 byte boundary */
80	if (offset) {
81		image_size += 2;
82		buf[1] = '\0';
83		write(out_fd, buf, 2);
84		update_checksum(buf, 2, sum);
85	}
86	return image_size;
87}
88
89void write_bugboot_header(int out_fd, uint32_t boot_size, uint16_t *sum)
90{
91	static bug_boot_header_t bbh = {
92		.magic_word = "BOOT",
93		.routine_name = "LINUXROM"
94	};
95
96	/* Fill in the PPCBUG ROM boot header */
97	bbh.entry_offset = htonl(HEADER_SIZE);	/* Entry address */
98	bbh.routine_length= htonl(HEADER_SIZE+boot_size+2);	/* Routine length */
99
100	/* Output the header and bootloader to the file */
101	write(out_fd, &bbh, sizeof(bug_boot_header_t));
102	update_checksum(&bbh, sizeof(bug_boot_header_t), sum);
103}
104
105int main(int argc, char *argv[])
106{
107	int image_fd, bugboot_fd;
108	uint32_t kernel_size = 0;
109	uint16_t checksum = 0;
110
111	if (argc != 3) {
112		fprintf(stderr, "usage: %s <kernel_image> <bugboot>\n",argv[0]);
113		exit(-1);
114	}
115
116	/* Get file args */
117
118	/* kernel image file */
119	if ((image_fd = open(argv[1] , 0)) < 0)
120		exit(-1);
121
122	/* bugboot file */
123	if (!strcmp(argv[2], "-"))
124		bugboot_fd = 1;			/* stdout */
125	else if ((bugboot_fd = creat(argv[2] , 0755)) < 0)
126		exit(-1);
127
128	/* Set file position after ROM header block where zImage will be written */
129	lseek(bugboot_fd, HEADER_SIZE, SEEK_SET);
130
131	/* Copy kernel image into bugboot image */
132	kernel_size = copy_image(image_fd, bugboot_fd, &checksum);
133
134	/* Set file position to beginning where header/romboot will be written */
135	lseek(bugboot_fd, 0, SEEK_SET);
136
137	/* Write out BUG header/romboot */
138	write_bugboot_header(bugboot_fd, kernel_size, &checksum);
139
140	/* Write out the calculated checksum */
141	lseek(bugboot_fd, 0, SEEK_END);
142	write(bugboot_fd, &checksum, 2);
143
144	/* Close bugboot file */
145	close(bugboot_fd);
146	return 0;
147}
148