drivers/mtd/afs.c

   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
  37 struct 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
  45 struct 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
  58 static 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
  69 static int
  70 afs_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
 128 static int
 129 afs_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
 164 static 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
 259 static struct mtd_part_parser afs_parser = {
 260         .owner = THIS_MODULE,
 261         .parse_fn = parse_afs_partitions,
 262         .name = "afs",
 263 };
 264
 265 static int __init afs_parser_init(void)
 266 {
 267         register_mtd_parser(&afs_parser);
 268         return 0;
 269 }
 270
 271 static void __exit afs_parser_exit(void)
 272 {
 273         deregister_mtd_parser(&afs_parser);
 274 }
 275
 276 module_init(afs_parser_init);
 277 module_exit(afs_parser_exit);
 278
 279
 280 MODULE_AUTHOR("ARM Ltd");
 281 MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
 282 MODULE_LICENSE("GPL");