1/*
2 * Makes a tree bootable image for IBM Evaluation boards.
3 * Basically, just take a zImage, skip the ELF header, and stuff
4 * a 32 byte header on the front.
5 *
6 * We use htonl, which is a network macro, to make sure we're doing
7 * The Right Thing on an LE machine.  It's non-obvious, but it should
8 * work on anything BSD'ish.
9 */
10
11#include <fcntl.h>
12#include <stdio.h>
13#include <stdlib.h>
14#include <string.h>
15#include <sys/stat.h>
16#include <unistd.h>
17#include <netinet/in.h>
18#ifdef __sun__
19#include <inttypes.h>
20#else
21#include <stdint.h>
22#endif
23
24/* This gets tacked on the front of the image.  There are also a few
25 * bytes allocated after the _start label used by the boot rom (see
26 * head.S for details).
27 */
28typedef struct boot_block {
29	uint32_t bb_magic;		/* 0x0052504F */
30	uint32_t bb_dest;		/* Target address of the image */
31	uint32_t bb_num_512blocks;	/* Size, rounded-up, in 512 byte blks */
32	uint32_t bb_debug_flag;	/* Run debugger or image after load */
33	uint32_t bb_entry_point;	/* The image address to start */
34	uint32_t bb_checksum;	/* 32 bit checksum including header */
35	uint32_t reserved[2];
36} boot_block_t;
37
38#define IMGBLK	512
39char	tmpbuf[IMGBLK];
40
41int main(int argc, char *argv[])
42{
43	int	in_fd, out_fd;
44	int	nblks, i;
45	uint	cksum, *cp;
46	struct	stat	st;
47	boot_block_t	bt;
48
49	if (argc < 5) {
50		fprintf(stderr, "usage: %s <zImage-file> <boot-image> <load address> <entry point>\n",argv[0]);
51		exit(1);
52	}
53
54	if (stat(argv[1], &st) < 0) {
55		perror("stat");
56		exit(2);
57	}
58
59	nblks = (st.st_size + IMGBLK) / IMGBLK;
60
61	bt.bb_magic = htonl(0x0052504F);
62
63	/* If we have the optional entry point parameter, use it */
64	bt.bb_dest = htonl(strtoul(argv[3], NULL, 0));
65	bt.bb_entry_point = htonl(strtoul(argv[4], NULL, 0));
66
67	/* We know these from the linker command.
68	 * ...and then move it up into memory a little more so the
69	 * relocation can happen.
70	 */
71	bt.bb_num_512blocks = htonl(nblks);
72	bt.bb_debug_flag = 0;
73
74	bt.bb_checksum = 0;
75
76	/* To be neat and tidy :-).
77	*/
78	bt.reserved[0] = 0;
79	bt.reserved[1] = 0;
80
81	if ((in_fd = open(argv[1], O_RDONLY)) < 0) {
82		perror("zImage open");
83		exit(3);
84	}
85
86	if ((out_fd = open(argv[2], (O_RDWR | O_CREAT | O_TRUNC), 0666)) < 0) {
87		perror("bootfile open");
88		exit(3);
89	}
90
91	cksum = 0;
92	cp = (void *)&bt;
93	for (i=0; i<sizeof(bt)/sizeof(uint); i++)
94		cksum += *cp++;
95
96	/* Assume zImage is an ELF file, and skip the 64K header.
97	*/
98	if (read(in_fd, tmpbuf, IMGBLK) != IMGBLK) {
99		fprintf(stderr, "%s is too small to be an ELF image\n",
100				argv[1]);
101		exit(4);
102	}
103
104	if ((*(uint *)tmpbuf) != htonl(0x7f454c46)) {
105		fprintf(stderr, "%s is not an ELF image\n", argv[1]);
106		exit(4);
107	}
108
109	if (lseek(in_fd, (64 * 1024), SEEK_SET) < 0) {
110		fprintf(stderr, "%s failed to seek in ELF image\n", argv[1]);
111		exit(4);
112	}
113
114	nblks -= (64 * 1024) / IMGBLK;
115
116	/* And away we go......
117	*/
118	if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) {
119		perror("boot-image write");
120		exit(5);
121	}
122
123	while (nblks-- > 0) {
124		if (read(in_fd, tmpbuf, IMGBLK) < 0) {
125			perror("zImage read");
126			exit(5);
127		}
128		cp = (uint *)tmpbuf;
129		for (i=0; i<sizeof(tmpbuf)/sizeof(uint); i++)
130			cksum += *cp++;
131		if (write(out_fd, tmpbuf, sizeof(tmpbuf)) != sizeof(tmpbuf)) {
132			perror("boot-image write");
133			exit(5);
134		}
135	}
136
137	/* rewrite the header with the computed checksum.
138	*/
139	bt.bb_checksum = htonl(cksum);
140	if (lseek(out_fd, 0, SEEK_SET) < 0) {
141		perror("rewrite seek");
142		exit(1);
143	}
144	if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) {
145		perror("boot-image rewrite");
146		exit(1);
147	}
148
149	exit(0);
150}
151