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_can_have_bb(master) &&
  82                        mtd_block_isbad(master, offset)) {
  83                         if (!offset) {
  84                         nogood:
  85                                 printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
  86                                 return -EIO;
  87                         }
  88                         offset -= master->erasesize;
  89                 }
  90         } else {
  91                 offset = directory * master->erasesize;
  92                 while (mtd_can_have_bb(master) &&
  93                        mtd_block_isbad(master, offset)) {
  94                         offset += master->erasesize;
  95                         if (offset == master->size)
  96                                 goto nogood;
  97                 }
  98         }
  99         buf = vmalloc(master->erasesize);
 100
 101         if (!buf)
 102                 return -ENOMEM;
 103
 104         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
 105                master->name, offset);
 106
 107         ret = mtd_read(master, offset, master->erasesize, &retlen,
 108                        (void *)buf);
 109
 110         if (ret)
 111                 goto out;
 112
 113         if (retlen != master->erasesize) {
 114                 ret = -EIO;
 115                 goto out;
 116         }
 117
 118         numslots = (master->erasesize / sizeof(struct fis_image_desc));
 119         for (i = 0; i < numslots; i++) {
 120                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
 121                         /* This is apparently the FIS directory entry for the
 122                          * FIS directory itself.  The FIS directory size is
 123                          * one erase block; if the buf[i].size field is
 124                          * swab32(erasesize) then we know we are looking at
 125                          * a byte swapped FIS directory - swap all the entries!
 126                          * (NOTE: this is 'size' not 'data_length'; size is
 127                          * the full size of the entry.)
 128                          */
 129
 130                         /* RedBoot can combine the FIS directory and
 131                            config partitions into a single eraseblock;
 132                            we assume wrong-endian if either the swapped
 133                            'size' matches the eraseblock size precisely,
 134                            or if the swapped size actually fits in an
 135                            eraseblock while the unswapped size doesn't. */
 136                         if (swab32(buf[i].size) == master->erasesize ||
 137                             (buf[i].size > master->erasesize
 138                              && swab32(buf[i].size) < master->erasesize)) {
 139                                 int j;
 140                                 /* Update numslots based on actual FIS directory size */
 141                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 142                                 for (j = 0; j < numslots; ++j) {
 143
 144                                         /* A single 0xff denotes a deleted entry.
 145                                          * Two of them in a row is the end of the table.
 146                                          */
 147                                         if (buf[j].name[0] == 0xff) {
 148                                                 if (buf[j].name[1] == 0xff) {
 149                                                         break;
 150                                                 } else {
 151                                                         continue;
 152                                                 }
 153                                         }
 154
 155                                         /* The unsigned long fields were written with the
 156                                          * wrong byte sex, name and pad have no byte sex.
 157                                          */
 158                                         swab32s(&buf[j].flash_base);
 159                                         swab32s(&buf[j].mem_base);
 160                                         swab32s(&buf[j].size);
 161                                         swab32s(&buf[j].entry_point);
 162                                         swab32s(&buf[j].data_length);
 163                                         swab32s(&buf[j].desc_cksum);
 164                                         swab32s(&buf[j].file_cksum);
 165                                 }
 166                         } else if (buf[i].size < master->erasesize) {
 167                                 /* Update numslots based on actual FIS directory size */
 168                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 169                         }
 170                         break;
 171                 }
 172         }
 173         if (i == numslots) {
 174                 /* Didn't find it */
 175                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 176                        master->name);
 177                 ret = 0;
 178                 goto out;
 179         }
 180
 181         for (i = 0; i < numslots; i++) {
 182                 struct fis_list *new_fl, **prev;
 183
 184                 if (buf[i].name[0] == 0xff) {
 185                         if (buf[i].name[1] == 0xff) {
 186                                 break;
 187                         } else {
 188                                 continue;
 189                         }
 190                 }
 191                 if (!redboot_checksum(&buf[i]))
 192                         break;
 193
 194                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 195                 namelen += strlen(buf[i].name)+1;
 196                 if (!new_fl) {
 197                         ret = -ENOMEM;
 198                         goto out;
 199                 }
 200                 new_fl->img = &buf[i];
 201                 if (data && data->origin)
 202                         buf[i].flash_base -= data->origin;
 203                 else
 204                         buf[i].flash_base &= master->size-1;
 205
 206                 /* I'm sure the JFFS2 code has done me permanent damage.
 207                  * I now think the following is _normal_
 208                  */
 209                 prev = &fl;
 210                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 211                         prev = &(*prev)->next;
 212                 new_fl->next = *prev;
 213                 *prev = new_fl;
 214
 215                 nrparts++;
 216         }
 217 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 218         if (fl->img->flash_base) {
 219                 nrparts++;
 220                 nulllen = sizeof(nullstring);
 221         }
 222
 223         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 224                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 225                         nrparts++;
 226                         nulllen = sizeof(nullstring);
 227                 }
 228         }
 229 #endif
 230         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 231
 232         if (!parts) {
 233                 ret = -ENOMEM;
 234                 goto out;
 235         }
 236
 237         nullname = (char *)&parts[nrparts];
 238 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 239         if (nulllen > 0) {
 240                 strcpy(nullname, nullstring);
 241         }
 242 #endif
 243         names = nullname + nulllen;
 244
 245         i=0;
 246
 247 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 248         if (fl->img->flash_base) {
 249                parts[0].name = nullname;
 250                parts[0].size = fl->img->flash_base;
 251                parts[0].offset = 0;
 252                 i++;
 253         }
 254 #endif
 255         for ( ; i<nrparts; i++) {
 256                 parts[i].size = fl->img->size;
 257                 parts[i].offset = fl->img->flash_base;
 258                 parts[i].name = names;
 259
 260                 strcpy(names, fl->img->name);
 261 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 262                 if (!memcmp(names, "RedBoot", 8) ||
 263                                 !memcmp(names, "RedBoot config", 15) ||
 264                                 !memcmp(names, "FIS directory", 14)) {
 265                         parts[i].mask_flags = MTD_WRITEABLE;
 266                 }
 267 #endif
 268                 names += strlen(names)+1;
 269
 270 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 271                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 272                         i++;
 273                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 274                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 275                         parts[i].name = nullname;
 276                 }
 277 #endif
 278                 tmp_fl = fl;
 279                 fl = fl->next;
 280                 kfree(tmp_fl);
 281         }
 282         ret = nrparts;
 283         *pparts = parts;
 284  out:
 285         while (fl) {
 286                 struct fis_list *old = fl;
 287                 fl = fl->next;
 288                 kfree(old);
 289         }
 290         vfree(buf);
 291         return ret;
 292 }
 293
 294 static struct mtd_part_parser redboot_parser = {
 295         .owner = THIS_MODULE,
 296         .parse_fn = parse_redboot_partitions,
 297         .name = "RedBoot",
 298 };
 299
 300 /* mtd parsers will request the module by parser name */
 301 MODULE_ALIAS("RedBoot");
 302
 303 static int __init redboot_parser_init(void)
 304 {
 305         return register_mtd_parser(&redboot_parser);
 306 }
 307
 308 static void __exit redboot_parser_exit(void)
 309 {
 310         deregister_mtd_parser(&redboot_parser);
 311 }
 312
 313 module_init(redboot_parser_init);
 314 module_exit(redboot_parser_exit);
 315
 316 MODULE_LICENSE("GPL");
 317 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 318 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");