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