drivers/mtd/parsers/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 #include <linux/of.h>
  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 void parse_redboot_of(struct mtd_info *master)
  60 {
  61         struct device_node *np;
  62         u32 dirblock;
  63         int ret;
  64
  65         np = mtd_get_of_node(master);
  66         if (!np)
  67                 return;
  68
  69         ret = of_property_read_u32(np, "fis-index-block", &dirblock);
  70         if (ret)
  71                 return;
  72
  73         /*
  74          * Assign the block found in the device tree to the local
  75          * directory block pointer.
  76          */
  77         directory = dirblock;
  78 }
  79
  80 static int parse_redboot_partitions(struct mtd_info *master,
  81                                     const struct mtd_partition **pparts,
  82                                     struct mtd_part_parser_data *data)
  83 {
  84         int nrparts = 0;
  85         struct fis_image_desc *buf;
  86         struct mtd_partition *parts;
  87         struct fis_list *fl = NULL, *tmp_fl;
  88         int ret, i;
  89         size_t retlen;
  90         char *names;
  91         char *nullname;
  92         int namelen = 0;
  93         int nulllen = 0;
  94         int numslots;
  95         unsigned long offset;
  96 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
  97         static char nullstring[] = "unallocated";
  98 #endif
  99
 100         parse_redboot_of(master);
 101
 102         if ( directory < 0 ) {
 103                 offset = master->size + directory * master->erasesize;
 104                 while (mtd_block_isbad(master, offset)) {
 105                         if (!offset) {
 106                         nogood:
 107                                 printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
 108                                 return -EIO;
 109                         }
 110                         offset -= master->erasesize;
 111                 }
 112         } else {
 113                 offset = directory * master->erasesize;
 114                 while (mtd_block_isbad(master, offset)) {
 115                         offset += master->erasesize;
 116                         if (offset == master->size)
 117                                 goto nogood;
 118                 }
 119         }
 120         buf = vmalloc(master->erasesize);
 121
 122         if (!buf)
 123                 return -ENOMEM;
 124
 125         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
 126                master->name, offset);
 127
 128         ret = mtd_read(master, offset, master->erasesize, &retlen,
 129                        (void *)buf);
 130
 131         if (ret)
 132                 goto out;
 133
 134         if (retlen != master->erasesize) {
 135                 ret = -EIO;
 136                 goto out;
 137         }
 138
 139         numslots = (master->erasesize / sizeof(struct fis_image_desc));
 140         for (i = 0; i < numslots; i++) {
 141                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
 142                         /* This is apparently the FIS directory entry for the
 143                          * FIS directory itself.  The FIS directory size is
 144                          * one erase block; if the buf[i].size field is
 145                          * swab32(erasesize) then we know we are looking at
 146                          * a byte swapped FIS directory - swap all the entries!
 147                          * (NOTE: this is 'size' not 'data_length'; size is
 148                          * the full size of the entry.)
 149                          */
 150
 151                         /* RedBoot can combine the FIS directory and
 152                            config partitions into a single eraseblock;
 153                            we assume wrong-endian if either the swapped
 154                            'size' matches the eraseblock size precisely,
 155                            or if the swapped size actually fits in an
 156                            eraseblock while the unswapped size doesn't. */
 157                         if (swab32(buf[i].size) == master->erasesize ||
 158                             (buf[i].size > master->erasesize
 159                              && swab32(buf[i].size) < master->erasesize)) {
 160                                 int j;
 161                                 /* Update numslots based on actual FIS directory size */
 162                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 163                                 for (j = 0; j < numslots; ++j) {
 164
 165                                         /* A single 0xff denotes a deleted entry.
 166                                          * Two of them in a row is the end of the table.
 167                                          */
 168                                         if (buf[j].name[0] == 0xff) {
 169                                                 if (buf[j].name[1] == 0xff) {
 170                                                         break;
 171                                                 } else {
 172                                                         continue;
 173                                                 }
 174                                         }
 175
 176                                         /* The unsigned long fields were written with the
 177                                          * wrong byte sex, name and pad have no byte sex.
 178                                          */
 179                                         swab32s(&buf[j].flash_base);
 180                                         swab32s(&buf[j].mem_base);
 181                                         swab32s(&buf[j].size);
 182                                         swab32s(&buf[j].entry_point);
 183                                         swab32s(&buf[j].data_length);
 184                                         swab32s(&buf[j].desc_cksum);
 185                                         swab32s(&buf[j].file_cksum);
 186                                 }
 187                         } else if (buf[i].size < master->erasesize) {
 188                                 /* Update numslots based on actual FIS directory size */
 189                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 190                         }
 191                         break;
 192                 }
 193         }
 194         if (i == numslots) {
 195                 /* Didn't find it */
 196                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 197                        master->name);
 198                 ret = 0;
 199                 goto out;
 200         }
 201
 202         for (i = 0; i < numslots; i++) {
 203                 struct fis_list *new_fl, **prev;
 204
 205                 if (buf[i].name[0] == 0xff) {
 206                         if (buf[i].name[1] == 0xff) {
 207                                 break;
 208                         } else {
 209                                 continue;
 210                         }
 211                 }
 212                 if (!redboot_checksum(&buf[i]))
 213                         break;
 214
 215                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 216                 namelen += strlen(buf[i].name)+1;
 217                 if (!new_fl) {
 218                         ret = -ENOMEM;
 219                         goto out;
 220                 }
 221                 new_fl->img = &buf[i];
 222                 if (data && data->origin)
 223                         buf[i].flash_base -= data->origin;
 224                 else
 225                         buf[i].flash_base &= master->size-1;
 226
 227                 /* I'm sure the JFFS2 code has done me permanent damage.
 228                  * I now think the following is _normal_
 229                  */
 230                 prev = &fl;
 231                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 232                         prev = &(*prev)->next;
 233                 new_fl->next = *prev;
 234                 *prev = new_fl;
 235
 236                 nrparts++;
 237         }
 238 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 239         if (fl->img->flash_base) {
 240                 nrparts++;
 241                 nulllen = sizeof(nullstring);
 242         }
 243
 244         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 245                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 246                         nrparts++;
 247                         nulllen = sizeof(nullstring);
 248                 }
 249         }
 250 #endif
 251         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 252
 253         if (!parts) {
 254                 ret = -ENOMEM;
 255                 goto out;
 256         }
 257
 258         nullname = (char *)&parts[nrparts];
 259 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 260         if (nulllen > 0) {
 261                 strcpy(nullname, nullstring);
 262         }
 263 #endif
 264         names = nullname + nulllen;
 265
 266         i=0;
 267
 268 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 269         if (fl->img->flash_base) {
 270                parts[0].name = nullname;
 271                parts[0].size = fl->img->flash_base;
 272                parts[0].offset = 0;
 273                 i++;
 274         }
 275 #endif
 276         for ( ; i<nrparts; i++) {
 277                 parts[i].size = fl->img->size;
 278                 parts[i].offset = fl->img->flash_base;
 279                 parts[i].name = names;
 280
 281                 strcpy(names, fl->img->name);
 282 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 283                 if (!memcmp(names, "RedBoot", 8) ||
 284                                 !memcmp(names, "RedBoot config", 15) ||
 285                                 !memcmp(names, "FIS directory", 14)) {
 286                         parts[i].mask_flags = MTD_WRITEABLE;
 287                 }
 288 #endif
 289                 names += strlen(names)+1;
 290
 291 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 292                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 293                         i++;
 294                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 295                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 296                         parts[i].name = nullname;
 297                 }
 298 #endif
 299                 tmp_fl = fl;
 300                 fl = fl->next;
 301                 kfree(tmp_fl);
 302         }
 303         ret = nrparts;
 304         *pparts = parts;
 305  out:
 306         while (fl) {
 307                 struct fis_list *old = fl;
 308                 fl = fl->next;
 309                 kfree(old);
 310         }
 311         vfree(buf);
 312         return ret;
 313 }
 314
 315 static const struct of_device_id mtd_parser_redboot_of_match_table[] = {
 316         { .compatible = "redboot-fis" },
 317         {},
 318 };
 319 MODULE_DEVICE_TABLE(of, mtd_parser_redboot_of_match_table);
 320
 321 static struct mtd_part_parser redboot_parser = {
 322         .parse_fn = parse_redboot_partitions,
 323         .name = "RedBoot",
 324         .of_match_table = mtd_parser_redboot_of_match_table,
 325 };
 326 module_mtd_part_parser(redboot_parser);
 327
 328 /* mtd parsers will request the module by parser name */
 329 MODULE_ALIAS("RedBoot");
 330 MODULE_LICENSE("GPL");
 331 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 332 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");