drivers/mtd/afs.c

   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 1.13 2004/02/27 22:09:59 rmk 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
  39 struct 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
  47 struct 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
  60 static 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
  71 static int
  72 afs_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
 130 static int
 131 afs_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
 166 static 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 = kmalloc(sz, GFP_KERNEL);
 211         if (!parts)
 212                 return -ENOMEM;
 213
 214         memset(parts, 0, sz);
 215         str = (char *)(parts + idx);
 216
 217         /*
 218          * Identify the partitions
 219          */
 220         for (idx = off = 0; off < mtd->size; off += mtd->erasesize) {
 221                 struct image_info_struct iis;
 222                 u_int iis_ptr, img_ptr, size;
 223
 224                 /* Read the footer. */
 225                 ret = afs_read_footer(mtd, &img_ptr, &iis_ptr, off, mask);
 226                 if (ret < 0)
 227                         break;
 228                 if (ret == 0)
 229                         continue;
 230
 231                 /* Read the image info block */
 232                 ret = afs_read_iis(mtd, &iis, iis_ptr);
 233                 if (ret < 0)
 234                         break;
 235                 if (ret == 0)
 236                         continue;
 237
 238                 strcpy(str, iis.name);
 239                 size = mtd->erasesize + off - img_ptr;
 240
 241                 /*
 242                  * In order to support JFFS2 partitions on this layout,
 243                  * we must lie to MTD about the real size of JFFS2
 244                  * partitions; this ensures that the AFS flash footer
 245                  * won't be erased by JFFS2.  Please ensure that your
 246                  * JFFS2 partitions are given image numbers between
 247                  * 1000 and 2000 inclusive.
 248                  */
 249                 if (iis.imageNumber >= 1000 && iis.imageNumber < 2000)
 250                         size -= mtd->erasesize;
 251
 252                 parts[idx].name         = str;
 253                 parts[idx].size         = size;
 254                 parts[idx].offset       = img_ptr;
 255                 parts[idx].mask_flags   = 0;
 256
 257                 printk("  mtd%d: at 0x%08x, %5dKB, %8u, %s\n",
 258                         idx, img_ptr, parts[idx].size / 1024,
 259                         iis.imageNumber, str);
 260
 261                 idx += 1;
 262                 str = str + strlen(iis.name) + 1;
 263         }
 264
 265         if (!idx) {
 266                 kfree(parts);
 267                 parts = NULL;
 268         }
 269
 270         *pparts = parts;
 271         return idx ? idx : ret;
 272 }
 273
 274 static struct mtd_part_parser afs_parser = {
 275         .owner = THIS_MODULE,
 276         .parse_fn = parse_afs_partitions,
 277         .name = "afs",
 278 };
 279
 280 static int __init afs_parser_init(void)
 281 {
 282         return register_mtd_parser(&afs_parser);
 283 }
 284
 285 static void __exit afs_parser_exit(void)
 286 {
 287         deregister_mtd_parser(&afs_parser);
 288 }
 289
 290 module_init(afs_parser_init);
 291 module_exit(afs_parser_exit);
 292
 293
 294 MODULE_AUTHOR("ARM Ltd");
 295 MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
 296 MODULE_LICENSE("GPL");