1/*======================================================================
2
3    drivers/mtd/afs.c: ARM Flash Layout/Partitioning
4
5    Copyright (C) 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   $Id: afs.c,v 1.1.1.1 2007/08/03 18:52:43 Exp $
25
26======================================================================*/
27
28#include <linux/module.h>
29#include <linux/types.h>
30#include <linux/kernel.h>
31#include <linux/slab.h>
32#include <linux/string.h>
33#include <linux/init.h>
34
35#include <linux/mtd/mtd.h>
36#include <linux/mtd/map.h>
37#include <linux/mtd/partitions.h>
38
39struct footer_struct {
40	u32 image_info_base;	/* Address of first word of ImageFooter  */
41	u32 image_start;	/* Start of area reserved by this footer */
42	u32 signature;		/* 'Magic' number proves it's a footer   */
43	u32 type;		/* Area type: ARM Image, SIB, customer   */
44	u32 checksum;		/* Just this structure                   */
45};
46
47struct image_info_struct {
48	u32 bootFlags;		/* Boot flags, compression etc.          */
49	u32 imageNumber;	/* Unique number, selects for boot etc.  */
50	u32 loadAddress;	/* Address program should be loaded to   */
51	u32 length;		/* Actual size of image                  */
52	u32 address;		/* Image is executed from here           */
53	char name[16];		/* Null terminated                       */
54	u32 headerBase;		/* Flash Address of any stripped header  */
55	u32 header_length;	/* Length of header in memory            */
56	u32 headerType;		/* AIF, RLF, s-record etc.               */
57	u32 checksum;		/* Image checksum (inc. this struct)     */
58};
59
60static u32 word_sum(void *words, int num)
61{
62	u32 *p = words;
63	u32 sum = 0;
64
65	while (num--)
66		sum += *p++;
67
68	return sum;
69}
70
71static int
72afs_read_footer(struct mtd_info *mtd, u_int *img_start, u_int *iis_start,
73		u_int off, u_int mask)
74{
75	struct footer_struct fs;
76	u_int ptr = off + mtd->erasesize - sizeof(fs);
77	size_t sz;
78	int ret;
79
80	ret = mtd->read(mtd, ptr, sizeof(fs), &sz, (u_char *) &fs);
81	if (ret >= 0 && sz != sizeof(fs))
82		ret = -EINVAL;
83
84	if (ret < 0) {
85		printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
86			ptr, ret);
87		return ret;
88	}
89
90	ret = 1;
91
92	/*
93	 * Does it contain the magic number?
94	 */
95	if (fs.signature != 0xa0ffff9f)
96		ret = 0;
97
98	/*
99	 * Check the checksum.
100	 */
101	if (word_sum(&fs, sizeof(fs) / sizeof(u32)) != 0xffffffff)
102		ret = 0;
103
104	/*
105	 * Don't touch the SIB.
106	 */
107	if (fs.type == 2)
108		ret = 0;
109
110	*iis_start = fs.image_info_base & mask;
111	*img_start = fs.image_start & mask;
112
113	/*
114	 * Check the image info base.  This can not
115	 * be located after the footer structure.
116	 */
117	if (*iis_start >= ptr)
118		ret = 0;
119
120	/*
121	 * Check the start of this image.  The image
122	 * data can not be located after this block.
123	 */
124	if (*img_start > off)
125		ret = 0;
126
127	return ret;
128}
129
130static int
131afs_read_iis(struct mtd_info *mtd, struct image_info_struct *iis, u_int ptr)
132{
133	size_t sz;
134	int ret, i;
135
136	memset(iis, 0, sizeof(*iis));
137	ret = mtd->read(mtd, ptr, sizeof(*iis), &sz, (u_char *) iis);
138	if (ret < 0)
139		goto failed;
140
141	if (sz != sizeof(*iis)) {
142		ret = -EINVAL;
143		goto failed;
144	}
145
146	ret = 0;
147
148	/*
149	 * Validate the name - it must be NUL terminated.
150	 */
151	for (i = 0; i < sizeof(iis->name); i++)
152		if (iis->name[i] == '\0')
153			break;
154
155	if (i < sizeof(iis->name))
156		ret = 1;
157
158	return ret;
159
160 failed:
161	printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
162		ptr, ret);
163	return ret;
164}
165
166static int parse_afs_partitions(struct mtd_info *mtd,
167                         struct mtd_partition **pparts,
168                         unsigned long origin)
169{
170	struct mtd_partition *parts;
171	u_int mask, off, idx, sz;
172	int ret = 0;
173	char *str;
174
175	/*
176	 * This is the address mask; we use this to mask off out of
177	 * range address bits.
178	 */
179	mask = mtd->size - 1;
180
181	/*
182	 * First, calculate the size of the array we need for the
183	 * partition information.  We include in this the size of
184	 * the strings.
185	 */
186	for (idx = off = sz = 0; off < mtd->size; off += mtd->erasesize) {
187		struct image_info_struct iis;
188		u_int iis_ptr, img_ptr;
189
190		ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
191		if (ret < 0)
192			break;
193		if (ret == 0)
194			continue;
195
196		ret = afs_read_iis(mtd, &iis, iis_ptr);
197		if (ret < 0)
198			break;
199		if (ret == 0)
200			continue;
201
202		sz += sizeof(struct mtd_partition);
203		sz += strlen(iis.name) + 1;
204		idx += 1;
205	}
206
207	if (!sz)
208		return ret;
209
210	parts = kzalloc(sz, GFP_KERNEL);
211	if (!parts)
212		return -ENOMEM;
213
214	str = (char *)(parts + idx);
215
216	/*
217	 * Identify the partitions
218	 */
219	for (idx = off = 0; off < mtd->size; off += mtd->erasesize) {
220		struct image_info_struct iis;
221		u_int iis_ptr, img_ptr;
222
223		/* Read the footer. */
224		ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
225		if (ret < 0)
226			break;
227		if (ret == 0)
228			continue;
229
230		/* Read the image info block */
231		ret = afs_read_iis(mtd, &iis, iis_ptr);
232		if (ret < 0)
233			break;
234		if (ret == 0)
235			continue;
236
237		strcpy(str, iis.name);
238
239		parts[idx].name		= str;
240		parts[idx].size		= (iis.length + mtd->erasesize - 1) & ~(mtd->erasesize - 1);
241		parts[idx].offset	= img_ptr;
242		parts[idx].mask_flags	= 0;
243
244		printk("  mtd%d: at 0x%08x, %5dKB, %8u, %s\n",
245			idx, img_ptr, parts[idx].size / 1024,
246			iis.imageNumber, str);
247
248		idx += 1;
249		str = str + strlen(iis.name) + 1;
250	}
251
252	if (!idx) {
253		kfree(parts);
254		parts = NULL;
255	}
256
257	*pparts = parts;
258	return idx ? idx : ret;
259}
260
261static struct mtd_part_parser afs_parser = {
262	.owner = THIS_MODULE,
263	.parse_fn = parse_afs_partitions,
264	.name = "afs",
265};
266
267static int __init afs_parser_init(void)
268{
269	return register_mtd_parser(&afs_parser);
270}
271
272static void __exit afs_parser_exit(void)
273{
274	deregister_mtd_parser(&afs_parser);
275}
276
277module_init(afs_parser_init);
278module_exit(afs_parser_exit);
279
280
281MODULE_AUTHOR("ARM Ltd");
282MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
283MODULE_LICENSE("GPL");
284