linux/drivers/mtd/afs.c
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   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        return register_mtd_parser(&afs_parser);
 268}
 269
 270static void __exit afs_parser_exit(void)
 271{
 272        deregister_mtd_parser(&afs_parser);
 273}
 274
 275module_init(afs_parser_init);
 276module_exit(afs_parser_exit);
 277
 278
 279MODULE_AUTHOR("ARM Ltd");
 280MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
 281MODULE_LICENSE("GPL");
 282
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