1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/*
* vrl4 format generator
*
* Copyright (C) 2010 Simon Horman
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
/*
* usage: vrl4 < zImage > out
* dd if=out of=/dev/sdx bs=512 seek=1 # Write the image to sector 1
*
* Reads a zImage from stdin and writes a vrl4 image to stdout.
* In practice this means writing a padded vrl4 header to stdout followed
* by the zImage.
*
* The padding places the zImage at ALIGN bytes into the output.
* The vrl4 uses ALIGN + START_BASE as the start_address.
* This is where the mask ROM will jump to after verifying the header.
*
* The header sets copy_size to min(sizeof(zImage), MAX_BOOT_PROG_LEN) + ALIGN.
* That is, the mask ROM will load the padded header (ALIGN bytes)
* And then MAX_BOOT_PROG_LEN bytes of the image, or the entire image,
* whichever is smaller.
*
* The zImage is not modified in any way.
*/
#define _BSD_SOURCE
#include <endian.h>
#include <unistd.h>
#include <stdint.h>
#include <stdio.h>
#include <errno.h>
#include <tools/endian.h>
struct hdr {
uint32_t magic1;
uint32_t reserved1;
uint32_t magic2;
uint32_t reserved2;
uint16_t copy_size;
uint16_t boot_options;
uint32_t reserved3;
uint32_t start_address;
uint32_t reserved4;
uint32_t reserved5;
char reserved6[308];
};
#define DECLARE_HDR(h) \
struct hdr (h) = { \
.magic1 = htole32(0xea000000), \
.reserved1 = htole32(0x56), \
.magic2 = htole32(0xe59ff008), \
.reserved3 = htole16(0x1) }
/* Align to 512 bytes, the MMCIF sector size */
#define ALIGN_BITS 9
#define ALIGN (1 << ALIGN_BITS)
#define START_BASE 0xe55b0000
/*
* With an alignment of 512 the header uses the first sector.
* There is a 128 sector (64kbyte) limit on the data loaded by the mask ROM.
* So there are 127 sectors left for the boot programme. But in practice
* Only a small portion of a zImage is needed, 16 sectors should be more
* than enough.
*
* Note that this sets how much of the zImage is copied by the mask ROM.
* The entire zImage is present after the header and is loaded
* by the code in the boot program (which is the first portion of the zImage).
*/
#define MAX_BOOT_PROG_LEN (16 * 512)
#define ROUND_UP(x) ((x + ALIGN - 1) & ~(ALIGN - 1))
static ssize_t do_read(int fd, void *buf, size_t count)
{
size_t offset = 0;
ssize_t l;
while (offset < count) {
l = read(fd, buf + offset, count - offset);
if (!l)
break;
if (l < 0) {
if (errno == EAGAIN || errno == EWOULDBLOCK)
continue;
perror("read");
return -1;
}
offset += l;
}
return offset;
}
static ssize_t do_write(int fd, const void *buf, size_t count)
{
size_t offset = 0;
ssize_t l;
while (offset < count) {
l = write(fd, buf + offset, count - offset);
if (l < 0) {
if (errno == EAGAIN || errno == EWOULDBLOCK)
continue;
perror("write");
return -1;
}
offset += l;
}
return offset;
}
static ssize_t write_zero(int fd, size_t len)
{
size_t i = len;
while (i--) {
const char x = 0;
if (do_write(fd, &x, 1) < 0)
return -1;
}
return len;
}
int main(void)
{
DECLARE_HDR(hdr);
char boot_program[MAX_BOOT_PROG_LEN];
size_t aligned_hdr_len, alligned_prog_len;
ssize_t prog_len;
prog_len = do_read(0, boot_program, sizeof(boot_program));
if (prog_len <= 0)
return -1;
aligned_hdr_len = ROUND_UP(sizeof(hdr));
hdr.start_address = htole32(START_BASE + aligned_hdr_len);
alligned_prog_len = ROUND_UP(prog_len);
hdr.copy_size = htole16(aligned_hdr_len + alligned_prog_len);
if (do_write(1, &hdr, sizeof(hdr)) < 0)
return -1;
if (write_zero(1, aligned_hdr_len - sizeof(hdr)) < 0)
return -1;
if (do_write(1, boot_program, prog_len) < 0)
return 1;
/* Write out the rest of the kernel */
while (1) {
prog_len = do_read(0, boot_program, sizeof(boot_program));
if (prog_len < 0)
return 1;
if (prog_len == 0)
break;
if (do_write(1, boot_program, prog_len) < 0)
return 1;
}
return 0;
}
|
