summaryrefslogtreecommitdiffstats
path: root/drivers/mtd/afs.c
blob: 801e6c7d08920e4c80babcb1c23bc239f4d869ab (plain)
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
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
/*======================================================================

    drivers/mtd/afs.c: ARM Flash Layout/Partitioning
  
    Copyright (C) 2000 ARM Limited
  
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
  
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
  
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  
   This is access code for flashes using ARM's flash partitioning 
   standards.

   $Id: afs.c,v 1.13 2004/02/27 22:09:59 rmk Exp $

======================================================================*/

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/init.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>

struct footer_struct {
	u32 image_info_base;	/* Address of first word of ImageFooter  */
	u32 image_start;	/* Start of area reserved by this footer */
	u32 signature;		/* 'Magic' number proves it's a footer   */
	u32 type;		/* Area type: ARM Image, SIB, customer   */
	u32 checksum;		/* Just this structure                   */
};

struct image_info_struct {
	u32 bootFlags;		/* Boot flags, compression etc.          */
	u32 imageNumber;	/* Unique number, selects for boot etc.  */
	u32 loadAddress;	/* Address program should be loaded to   */
	u32 length;		/* Actual size of image                  */
	u32 address;		/* Image is executed from here           */
	char name[16];		/* Null terminated                       */
	u32 headerBase;		/* Flash Address of any stripped header  */
	u32 header_length;	/* Length of header in memory            */
	u32 headerType;		/* AIF, RLF, s-record etc.               */
	u32 checksum;		/* Image checksum (inc. this struct)     */
};

static u32 word_sum(void *words, int num)
{
	u32 *p = words;
	u32 sum = 0;

	while (num--)
		sum += *p++;

	return sum;
}

static int
afs_read_footer(struct mtd_info *mtd, u_int *img_start, u_int *iis_start,
		u_int off, u_int mask)
{
	struct footer_struct fs;
	u_int ptr = off + mtd->erasesize - sizeof(fs);
	size_t sz;
	int ret;

	ret = mtd->read(mtd, ptr, sizeof(fs), &sz, (u_char *) &fs);
	if (ret >= 0 && sz != sizeof(fs))
		ret = -EINVAL;

	if (ret < 0) {
		printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
			ptr, ret);
		return ret;
	}

	ret = 1;

	/*
	 * Does it contain the magic number?
	 */
	if (fs.signature != 0xa0ffff9f)
		ret = 0;

	/*
	 * Check the checksum.
	 */
	if (word_sum(&fs, sizeof(fs) / sizeof(u32)) != 0xffffffff)
		ret = 0;

	/*
	 * Don't touch the SIB.
	 */
	if (fs.type == 2)
		ret = 0;

	*iis_start = fs.image_info_base & mask;
	*img_start = fs.image_start & mask;

	/*
	 * Check the image info base.  This can not
	 * be located after the footer structure.
	 */
	if (*iis_start >= ptr)
		ret = 0;

	/*
	 * Check the start of this image.  The image
	 * data can not be located after this block.
	 */
	if (*img_start > off)
		ret = 0;

	return ret;
}

static int
afs_read_iis(struct mtd_info *mtd, struct image_info_struct *iis, u_int ptr)
{
	size_t sz;
	int ret, i;

	memset(iis, 0, sizeof(*iis));
	ret = mtd->read(mtd, ptr, sizeof(*iis), &sz, (u_char *) iis);
	if (ret < 0)
		goto failed;

	if (sz != sizeof(*iis)) {
		ret = -EINVAL;
		goto failed;
	}

	ret = 0;

	/*
	 * Validate the name - it must be NUL terminated.
	 */
	for (i = 0; i < sizeof(iis->name); i++)
		if (iis->name[i] == '\0')
			break;

	if (i < sizeof(iis->name))
		ret = 1;

	return ret;

 failed:
	printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
		ptr, ret);
	return ret;
}

static int parse_afs_partitions(struct mtd_info *mtd, 
                         struct mtd_partition **pparts,
                         unsigned long origin)
{
	struct mtd_partition *parts;
	u_int mask, off, idx, sz;
	int ret = 0;
	char *str;

	/*
	 * This is the address mask; we use this to mask off out of
	 * range address bits.
	 */
	mask = mtd->size - 1;

	/*
	 * First, calculate the size of the array we need for the
	 * partition information.  We include in this the size of
	 * the strings.
	 */
	for (idx = off = sz = 0; off < mtd->size; off += mtd->erasesize) {
		struct image_info_struct iis;
		u_int iis_ptr, img_ptr;

		ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
		if (ret < 0)
			break;
		if (ret == 0)
			continue;

		ret = afs_read_iis(mtd, &iis, iis_ptr);
		if (ret < 0)
			break;
		if (ret == 0)
			continue;

		sz += sizeof(struct mtd_partition);
		sz += strlen(iis.name) + 1;
		idx += 1;
	}

	if (!sz)
		return ret;

	parts = kmalloc(sz, GFP_KERNEL);
	if (!parts)
		return -ENOMEM;

	memset(parts, 0, sz);
	str = (char *)(parts + idx);

	/*
	 * Identify the partitions
	 */
	for (idx = off = 0; off < mtd->size; off += mtd->erasesize) {
		struct image_info_struct iis;
		u_int iis_ptr, img_ptr, size;

		/* Read the footer. */
		ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
		if (ret < 0)
			break;
		if (ret == 0)
			continue;

		/* Read the image info block */
		ret = afs_read_iis(mtd, &iis, iis_ptr);
		if (ret < 0)
			break;
		if (ret == 0)
			continue;

		strcpy(str, iis.name);
		size = mtd->erasesize + off - img_ptr;

		/*
		 * In order to support JFFS2 partitions on this layout,
		 * we must lie to MTD about the real size of JFFS2
		 * partitions; this ensures that the AFS flash footer
		 * won't be erased by JFFS2.  Please ensure that your
		 * JFFS2 partitions are given image numbers between
		 * 1000 and 2000 inclusive.
		 */
		if (iis.imageNumber >= 1000 && iis.imageNumber < 2000)
			size -= mtd->erasesize;

		parts[idx].name		= str;
		parts[idx].size		= size;
		parts[idx].offset	= img_ptr;
		parts[idx].mask_flags	= 0;

		printk("  mtd%d: at 0x%08x, %5dKB, %8u, %s\n",
			idx, img_ptr, parts[idx].size / 1024,
			iis.imageNumber, str);

		idx += 1;
		str = str + strlen(iis.name) + 1;
	}

	if (!idx) {
		kfree(parts);
		parts = NULL;
	}

	*pparts = parts;
	return idx ? idx : ret;
}

static struct mtd_part_parser afs_parser = {
	.owner = THIS_MODULE,
	.parse_fn = parse_afs_partitions,
	.name = "afs",
};

static int __init afs_parser_init(void)
{
	return register_mtd_parser(&afs_parser);
}

static void __exit afs_parser_exit(void)
{
	deregister_mtd_parser(&afs_parser);
}

module_init(afs_parser_init);
module_exit(afs_parser_exit);


MODULE_AUTHOR("ARM Ltd");
MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
MODULE_LICENSE("GPL");