drivers/mtd/redboot.c

   1 /*
   2  * Parse RedBoot-style Flash Image System (FIS) tables and
   3  * produce a Linux partition array to match.
   4  *
   5  * Copyright © 2001      Red Hat UK Limited
   6  * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21  *
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <linux/slab.h>
  26 #include <linux/init.h>
  27 #include <linux/vmalloc.h>
  28
  29 #include <linux/mtd/mtd.h>
  30 #include <linux/mtd/partitions.h>
  31 #include <linux/module.h>
  32
  33 struct fis_image_desc {
  34     unsigned char name[16];      // Null terminated name
  35     uint32_t      flash_base;    // Address within FLASH of image
  36     uint32_t      mem_base;      // Address in memory where it executes
  37     uint32_t      size;          // Length of image
  38     uint32_t      entry_point;   // Execution entry point
  39     uint32_t      data_length;   // Length of actual data
  40     unsigned char _pad[256-(16+7*sizeof(uint32_t))];
  41     uint32_t      desc_cksum;    // Checksum over image descriptor
  42     uint32_t      file_cksum;    // Checksum over image data
  43 };
  44
  45 struct fis_list {
  46         struct fis_image_desc *img;
  47         struct fis_list *next;
  48 };
  49
  50 static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
  51 module_param(directory, int, 0);
  52
  53 static inline int redboot_checksum(struct fis_image_desc *img)
  54 {
  55         /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
  56         return 1;
  57 }
  58
  59 static int parse_redboot_partitions(struct mtd_info *master,
  60                                     struct mtd_partition **pparts,
  61                                     struct mtd_part_parser_data *data)
  62 {
  63         int nrparts = 0;
  64         struct fis_image_desc *buf;
  65         struct mtd_partition *parts;
  66         struct fis_list *fl = NULL, *tmp_fl;
  67         int ret, i;
  68         size_t retlen;
  69         char *names;
  70         char *nullname;
  71         int namelen = 0;
  72         int nulllen = 0;
  73         int numslots;
  74         unsigned long offset;
  75 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
  76         static char nullstring[] = "unallocated";
  77 #endif
  78
  79         if ( directory < 0 ) {
  80                 offset = master->size + directory * master->erasesize;
  81                 while (mtd_block_isbad(master, offset)) {
  82                         if (!offset) {
  83                         nogood:
  84                                 printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
  85                                 return -EIO;
  86                         }
  87                         offset -= master->erasesize;
  88                 }
  89         } else {
  90                 offset = directory * master->erasesize;
  91                 while (mtd_block_isbad(master, offset)) {
  92                         offset += master->erasesize;
  93                         if (offset == master->size)
  94                                 goto nogood;
  95                 }
  96         }
  97         buf = vmalloc(master->erasesize);
  98
  99         if (!buf)
 100                 return -ENOMEM;
 101
 102         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
 103                master->name, offset);
 104
 105         ret = mtd_read(master, offset, master->erasesize, &retlen,
 106                        (void *)buf);
 107
 108         if (ret)
 109                 goto out;
 110
 111         if (retlen != master->erasesize) {
 112                 ret = -EIO;
 113                 goto out;
 114         }
 115
 116         numslots = (master->erasesize / sizeof(struct fis_image_desc));
 117         for (i = 0; i < numslots; i++) {
 118                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
 119                         /* This is apparently the FIS directory entry for the
 120                          * FIS directory itself.  The FIS directory size is
 121                          * one erase block; if the buf[i].size field is
 122                          * swab32(erasesize) then we know we are looking at
 123                          * a byte swapped FIS directory - swap all the entries!
 124                          * (NOTE: this is 'size' not 'data_length'; size is
 125                          * the full size of the entry.)
 126                          */
 127
 128                         /* RedBoot can combine the FIS directory and
 129                            config partitions into a single eraseblock;
 130                            we assume wrong-endian if either the swapped
 131                            'size' matches the eraseblock size precisely,
 132                            or if the swapped size actually fits in an
 133                            eraseblock while the unswapped size doesn't. */
 134                         if (swab32(buf[i].size) == master->erasesize ||
 135                             (buf[i].size > master->erasesize
 136                              && swab32(buf[i].size) < master->erasesize)) {
 137                                 int j;
 138                                 /* Update numslots based on actual FIS directory size */
 139                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 140                                 for (j = 0; j < numslots; ++j) {
 141
 142                                         /* A single 0xff denotes a deleted entry.
 143                                          * Two of them in a row is the end of the table.
 144                                          */
 145                                         if (buf[j].name[0] == 0xff) {
 146                                                 if (buf[j].name[1] == 0xff) {
 147                                                         break;
 148                                                 } else {
 149                                                         continue;
 150                                                 }
 151                                         }
 152
 153                                         /* The unsigned long fields were written with the
 154                                          * wrong byte sex, name and pad have no byte sex.
 155                                          */
 156                                         swab32s(&buf[j].flash_base);
 157                                         swab32s(&buf[j].mem_base);
 158                                         swab32s(&buf[j].size);
 159                                         swab32s(&buf[j].entry_point);
 160                                         swab32s(&buf[j].data_length);
 161                                         swab32s(&buf[j].desc_cksum);
 162                                         swab32s(&buf[j].file_cksum);
 163                                 }
 164                         } else if (buf[i].size < master->erasesize) {
 165                                 /* Update numslots based on actual FIS directory size */
 166                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 167                         }
 168                         break;
 169                 }
 170         }
 171         if (i == numslots) {
 172                 /* Didn't find it */
 173                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 174                        master->name);
 175                 ret = 0;
 176                 goto out;
 177         }
 178
 179         for (i = 0; i < numslots; i++) {
 180                 struct fis_list *new_fl, **prev;
 181
 182                 if (buf[i].name[0] == 0xff) {
 183                         if (buf[i].name[1] == 0xff) {
 184                                 break;
 185                         } else {
 186                                 continue;
 187                         }
 188                 }
 189                 if (!redboot_checksum(&buf[i]))
 190                         break;
 191
 192                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 193                 namelen += strlen(buf[i].name)+1;
 194                 if (!new_fl) {
 195                         ret = -ENOMEM;
 196                         goto out;
 197                 }
 198                 new_fl->img = &buf[i];
 199                 if (data && data->origin)
 200                         buf[i].flash_base -= data->origin;
 201                 else
 202                         buf[i].flash_base &= master->size-1;
 203
 204                 /* I'm sure the JFFS2 code has done me permanent damage.
 205                  * I now think the following is _normal_
 206                  */
 207                 prev = &fl;
 208                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 209                         prev = &(*prev)->next;
 210                 new_fl->next = *prev;
 211                 *prev = new_fl;
 212
 213                 nrparts++;
 214         }
 215 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 216         if (fl->img->flash_base) {
 217                 nrparts++;
 218                 nulllen = sizeof(nullstring);
 219         }
 220
 221         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 222                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 223                         nrparts++;
 224                         nulllen = sizeof(nullstring);
 225                 }
 226         }
 227 #endif
 228         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 229
 230         if (!parts) {
 231                 ret = -ENOMEM;
 232                 goto out;
 233         }
 234
 235         nullname = (char *)&parts[nrparts];
 236 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 237         if (nulllen > 0) {
 238                 strcpy(nullname, nullstring);
 239         }
 240 #endif
 241         names = nullname + nulllen;
 242
 243         i=0;
 244
 245 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 246         if (fl->img->flash_base) {
 247                parts[0].name = nullname;
 248                parts[0].size = fl->img->flash_base;
 249                parts[0].offset = 0;
 250                 i++;
 251         }
 252 #endif
 253         for ( ; i<nrparts; i++) {
 254                 parts[i].size = fl->img->size;
 255                 parts[i].offset = fl->img->flash_base;
 256                 parts[i].name = names;
 257
 258                 strcpy(names, fl->img->name);
 259 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 260                 if (!memcmp(names, "RedBoot", 8) ||
 261                                 !memcmp(names, "RedBoot config", 15) ||
 262                                 !memcmp(names, "FIS directory", 14)) {
 263                         parts[i].mask_flags = MTD_WRITEABLE;
 264                 }
 265 #endif
 266                 names += strlen(names)+1;
 267
 268 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 269                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 270                         i++;
 271                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 272                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 273                         parts[i].name = nullname;
 274                 }
 275 #endif
 276                 tmp_fl = fl;
 277                 fl = fl->next;
 278                 kfree(tmp_fl);
 279         }
 280         ret = nrparts;
 281         *pparts = parts;
 282  out:
 283         while (fl) {
 284                 struct fis_list *old = fl;
 285                 fl = fl->next;
 286                 kfree(old);
 287         }
 288         vfree(buf);
 289         return ret;
 290 }
 291
 292 static struct mtd_part_parser redboot_parser = {
 293         .owner = THIS_MODULE,
 294         .parse_fn = parse_redboot_partitions,
 295         .name = "RedBoot",
 296 };
 297
 298 /* mtd parsers will request the module by parser name */
 299 MODULE_ALIAS("RedBoot");
 300
 301 static int __init redboot_parser_init(void)
 302 {
 303         register_mtd_parser(&redboot_parser);
 304         return 0;
 305 }
 306
 307 static void __exit redboot_parser_exit(void)
 308 {
 309         deregister_mtd_parser(&redboot_parser);
 310 }
 311
 312 module_init(redboot_parser_init);
 313 module_exit(redboot_parser_exit);
 314
 315 MODULE_LICENSE("GPL");
 316 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 317 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");