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
  32 struct fis_image_desc {
  33     unsigned char name[16];      // Null terminated name
  34     uint32_t      flash_base;    // Address within FLASH of image
  35     uint32_t      mem_base;      // Address in memory where it executes
  36     uint32_t      size;          // Length of image
  37     uint32_t      entry_point;   // Execution entry point
  38     uint32_t      data_length;   // Length of actual data
  39     unsigned char _pad[256-(16+7*sizeof(uint32_t))];
  40     uint32_t      desc_cksum;    // Checksum over image descriptor
  41     uint32_t      file_cksum;    // Checksum over image data
  42 };
  43
  44 struct fis_list {
  45         struct fis_image_desc *img;
  46         struct fis_list *next;
  47 };
  48
  49 static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
  50 module_param(directory, int, 0);
  51
  52 static inline int redboot_checksum(struct fis_image_desc *img)
  53 {
  54         /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
  55         return 1;
  56 }
  57
  58 static int parse_redboot_partitions(struct mtd_info *master,
  59                              struct mtd_partition **pparts,
  60                              unsigned long fis_origin)
  61 {
  62         int nrparts = 0;
  63         struct fis_image_desc *buf;
  64         struct mtd_partition *parts;
  65         struct fis_list *fl = NULL, *tmp_fl;
  66         int ret, i;
  67         size_t retlen;
  68         char *names;
  69         char *nullname;
  70         int namelen = 0;
  71         int nulllen = 0;
  72         int numslots;
  73         unsigned long offset;
  74 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
  75         static char nullstring[] = "unallocated";
  76 #endif
  77
  78         if ( directory < 0 ) {
  79                 offset = master->size + directory * master->erasesize;
  80                 while (master->block_isbad &&
  81                        master->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 (master->block_isbad &&
  92                        master->block_isbad(master, offset)) {
  93                         offset += master->erasesize;
  94                         if (offset == master->size)
  95                                 goto nogood;
  96                 }
  97         }
  98         buf = vmalloc(master->erasesize);
  99
 100         if (!buf)
 101                 return -ENOMEM;
 102
 103         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
 104                master->name, offset);
 105
 106         ret = master->read(master, offset,
 107                            master->erasesize, &retlen, (void *)buf);
 108
 109         if (ret)
 110                 goto out;
 111
 112         if (retlen != master->erasesize) {
 113                 ret = -EIO;
 114                 goto out;
 115         }
 116
 117         numslots = (master->erasesize / sizeof(struct fis_image_desc));
 118         for (i = 0; i < numslots; i++) {
 119                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
 120                         /* This is apparently the FIS directory entry for the
 121                          * FIS directory itself.  The FIS directory size is
 122                          * one erase block; if the buf[i].size field is
 123                          * swab32(erasesize) then we know we are looking at
 124                          * a byte swapped FIS directory - swap all the entries!
 125                          * (NOTE: this is 'size' not 'data_length'; size is
 126                          * the full size of the entry.)
 127                          */
 128
 129                         /* RedBoot can combine the FIS directory and
 130                            config partitions into a single eraseblock;
 131                            we assume wrong-endian if either the swapped
 132                            'size' matches the eraseblock size precisely,
 133                            or if the swapped size actually fits in an
 134                            eraseblock while the unswapped size doesn't. */
 135                         if (swab32(buf[i].size) == master->erasesize ||
 136                             (buf[i].size > master->erasesize
 137                              && swab32(buf[i].size) < master->erasesize)) {
 138                                 int j;
 139                                 /* Update numslots based on actual FIS directory size */
 140                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 141                                 for (j = 0; j < numslots; ++j) {
 142
 143                                         /* A single 0xff denotes a deleted entry.
 144                                          * Two of them in a row is the end of the table.
 145                                          */
 146                                         if (buf[j].name[0] == 0xff) {
 147                                                 if (buf[j].name[1] == 0xff) {
 148                                                         break;
 149                                                 } else {
 150                                                         continue;
 151                                                 }
 152                                         }
 153
 154                                         /* The unsigned long fields were written with the
 155                                          * wrong byte sex, name and pad have no byte sex.
 156                                          */
 157                                         swab32s(&buf[j].flash_base);
 158                                         swab32s(&buf[j].mem_base);
 159                                         swab32s(&buf[j].size);
 160                                         swab32s(&buf[j].entry_point);
 161                                         swab32s(&buf[j].data_length);
 162                                         swab32s(&buf[j].desc_cksum);
 163                                         swab32s(&buf[j].file_cksum);
 164                                 }
 165                         } else if (buf[i].size < master->erasesize) {
 166                                 /* Update numslots based on actual FIS directory size */
 167                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 168                         }
 169                         break;
 170                 }
 171         }
 172         if (i == numslots) {
 173                 /* Didn't find it */
 174                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 175                        master->name);
 176                 ret = 0;
 177                 goto out;
 178         }
 179
 180         for (i = 0; i < numslots; i++) {
 181                 struct fis_list *new_fl, **prev;
 182
 183                 if (buf[i].name[0] == 0xff) {
 184                         if (buf[i].name[1] == 0xff) {
 185                                 break;
 186                         } else {
 187                                 continue;
 188                         }
 189                 }
 190                 if (!redboot_checksum(&buf[i]))
 191                         break;
 192
 193                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 194                 namelen += strlen(buf[i].name)+1;
 195                 if (!new_fl) {
 196                         ret = -ENOMEM;
 197                         goto out;
 198                 }
 199                 new_fl->img = &buf[i];
 200                 if (fis_origin) {
 201                         buf[i].flash_base -= fis_origin;
 202                 } else {
 203                         buf[i].flash_base &= master->size-1;
 204                 }
 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 static int __init redboot_parser_init(void)
 301 {
 302         return register_mtd_parser(&redboot_parser);
 303 }
 304
 305 static void __exit redboot_parser_exit(void)
 306 {
 307         deregister_mtd_parser(&redboot_parser);
 308 }
 309
 310 module_init(redboot_parser_init);
 311 module_exit(redboot_parser_exit);
 312
 313 MODULE_LICENSE("GPL");
 314 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 315 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");