1/*======================================================================
2
3    drivers/mtd/afs.c: ARM Flash Layout/Partitioning
4
5    Copyright © 2000 ARM Limited
6
7   This program is free software; you can redistribute it and/or modify
8   it under the terms of the GNU General Public License as published by
9   the Free Software Foundation; either version 2 of the License, or
10   (at your option) any later version.
11
12   This program is distributed in the hope that it will be useful,
13   but WITHOUT ANY WARRANTY; without even the implied warranty of
14   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15   GNU General Public License for more details.
16
17   You should have received a copy of the GNU General Public License
18   along with this program; if not, write to the Free Software
19   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
20
21   This is access code for flashes using ARM's flash partitioning
22   standards.
23
24======================================================================*/
25
26#include <linux/module.h>
27#include <linux/types.h>
28#include <linux/kernel.h>
29#include <linux/slab.h>
30#include <linux/string.h>
31#include <linux/init.h>
32
33#include <linux/mtd/mtd.h>
34#include <linux/mtd/map.h>
35#include <linux/mtd/partitions.h>
36
37struct footer_struct {
38	u32 image_info_base;	/* Address of first word of ImageFooter  */
39	u32 image_start;	/* Start of area reserved by this footer */
40	u32 signature;		/* 'Magic' number proves it's a footer   */
41	u32 type;		/* Area type: ARM Image, SIB, customer   */
42	u32 checksum;		/* Just this structure                   */
43};
44
45struct image_info_struct {
46	u32 bootFlags;		/* Boot flags, compression etc.          */
47	u32 imageNumber;	/* Unique number, selects for boot etc.  */
48	u32 loadAddress;	/* Address program should be loaded to   */
49	u32 length;		/* Actual size of image                  */
50	u32 address;		/* Image is executed from here           */
51	char name[16];		/* Null terminated                       */
52	u32 headerBase;		/* Flash Address of any stripped header  */
53	u32 header_length;	/* Length of header in memory            */
54	u32 headerType;		/* AIF, RLF, s-record etc.               */
55	u32 checksum;		/* Image checksum (inc. this struct)     */
56};
57
58static u32 word_sum(void *words, int num)
59{
60	u32 *p = words;
61	u32 sum = 0;
62
63	while (num--)
64		sum += *p++;
65
66	return sum;
67}
68
69static int
70afs_read_footer(struct mtd_info *mtd, u_int *img_start, u_int *iis_start,
71		u_int off, u_int mask)
72{
73	struct footer_struct fs;
74	u_int ptr = off + mtd->erasesize - sizeof(fs);
75	size_t sz;
76	int ret;
77
78	ret = mtd_read(mtd, ptr, sizeof(fs), &sz, (u_char *)&fs);
79	if (ret >= 0 && sz != sizeof(fs))
80		ret = -EINVAL;
81
82	if (ret < 0) {
83		printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
84			ptr, ret);
85		return ret;
86	}
87
88	ret = 1;
89
90	/*
91	 * Does it contain the magic number?
92	 */
93	if (fs.signature != 0xa0ffff9f)
94		ret = 0;
95
96	/*
97	 * Check the checksum.
98	 */
99	if (word_sum(&fs, sizeof(fs) / sizeof(u32)) != 0xffffffff)
100		ret = 0;
101
102	/*
103	 * Don't touch the SIB.
104	 */
105	if (fs.type == 2)
106		ret = 0;
107
108	*iis_start = fs.image_info_base & mask;
109	*img_start = fs.image_start & mask;
110
111	/*
112	 * Check the image info base.  This can not
113	 * be located after the footer structure.
114	 */
115	if (*iis_start >= ptr)
116		ret = 0;
117
118	/*
119	 * Check the start of this image.  The image
120	 * data can not be located after this block.
121	 */
122	if (*img_start > off)
123		ret = 0;
124
125	return ret;
126}
127
128static int
129afs_read_iis(struct mtd_info *mtd, struct image_info_struct *iis, u_int ptr)
130{
131	size_t sz;
132	int ret, i;
133
134	memset(iis, 0, sizeof(*iis));
135	ret = mtd_read(mtd, ptr, sizeof(*iis), &sz, (u_char *)iis);
136	if (ret < 0)
137		goto failed;
138
139	if (sz != sizeof(*iis)) {
140		ret = -EINVAL;
141		goto failed;
142	}
143
144	ret = 0;
145
146	/*
147	 * Validate the name - it must be NUL terminated.
148	 */
149	for (i = 0; i < sizeof(iis->name); i++)
150		if (iis->name[i] == '\0')
151			break;
152
153	if (i < sizeof(iis->name))
154		ret = 1;
155
156	return ret;
157
158 failed:
159	printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
160		ptr, ret);
161	return ret;
162}
163
164static int parse_afs_partitions(struct mtd_info *mtd,
165				struct mtd_partition **pparts,
166				struct mtd_part_parser_data *data)
167{
168	struct mtd_partition *parts;
169	u_int mask, off, idx, sz;
170	int ret = 0;
171	char *str;
172
173	/*
174	 * This is the address mask; we use this to mask off out of
175	 * range address bits.
176	 */
177	mask = mtd->size - 1;
178
179	/*
180	 * First, calculate the size of the array we need for the
181	 * partition information.  We include in this the size of
182	 * the strings.
183	 */
184	for (idx = off = sz = 0; off < mtd->size; off += mtd->erasesize) {
185		struct image_info_struct iis;
186		u_int iis_ptr, img_ptr;
187
188		ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
189		if (ret < 0)
190			break;
191		if (ret == 0)
192			continue;
193
194		ret = afs_read_iis(mtd, &iis, iis_ptr);
195		if (ret < 0)
196			break;
197		if (ret == 0)
198			continue;
199
200		sz += sizeof(struct mtd_partition);
201		sz += strlen(iis.name) + 1;
202		idx += 1;
203	}
204
205	if (!sz)
206		return ret;
207
208	parts = kzalloc(sz, GFP_KERNEL);
209	if (!parts)
210		return -ENOMEM;
211
212	str = (char *)(parts + idx);
213
214	/*
215	 * Identify the partitions
216	 */
217	for (idx = off = 0; off < mtd->size; off += mtd->erasesize) {
218		struct image_info_struct iis;
219		u_int iis_ptr, img_ptr;
220
221		/* Read the footer. */
222		ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
223		if (ret < 0)
224			break;
225		if (ret == 0)
226			continue;
227
228		/* Read the image info block */
229		ret = afs_read_iis(mtd, &iis, iis_ptr);
230		if (ret < 0)
231			break;
232		if (ret == 0)
233			continue;
234
235		strcpy(str, iis.name);
236
237		parts[idx].name		= str;
238		parts[idx].size		= (iis.length + mtd->erasesize - 1) & ~(mtd->erasesize - 1);
239		parts[idx].offset	= img_ptr;
240		parts[idx].mask_flags	= 0;
241
242		printk("  mtd%d: at 0x%08x, %5lluKiB, %8u, %s\n",
243			idx, img_ptr, parts[idx].size / 1024,
244			iis.imageNumber, str);
245
246		idx += 1;
247		str = str + strlen(iis.name) + 1;
248	}
249
250	if (!idx) {
251		kfree(parts);
252		parts = NULL;
253	}
254
255	*pparts = parts;
256	return idx ? idx : ret;
257}
258
259static struct mtd_part_parser afs_parser = {
260	.owner = THIS_MODULE,
261	.parse_fn = parse_afs_partitions,
262	.name = "afs",
263};
264
265static int __init afs_parser_init(void)
266{
267	register_mtd_parser(&afs_parser);
268	return 0;
269}
270
271static void __exit afs_parser_exit(void)
272{
273	deregister_mtd_parser(&afs_parser);
274}
275
276module_init(afs_parser_init);
277module_exit(afs_parser_exit);
278
279
280MODULE_AUTHOR("ARM Ltd");
281MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
282MODULE_LICENSE("GPL");
283