drivers/mtd/redboot.c

   1 /*
   2  * $Id: redboot.c,v 1.21 2006/03/30 18:34:37 bjd Exp $
   3  *
   4  * Parse RedBoot-style Flash Image System (FIS) tables and
   5  * produce a Linux partition array to match.
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10 #include <linux/init.h>
  11 #include <linux/vmalloc.h>
  12
  13 #include <linux/mtd/mtd.h>
  14 #include <linux/mtd/partitions.h>
  15
  16 struct fis_image_desc {
  17     unsigned char name[16];      // Null terminated name
  18     uint32_t      flash_base;    // Address within FLASH of image
  19     uint32_t      mem_base;      // Address in memory where it executes
  20     uint32_t      size;          // Length of image
  21     uint32_t      entry_point;   // Execution entry point
  22     uint32_t      data_length;   // Length of actual data
  23     unsigned char _pad[256-(16+7*sizeof(uint32_t))];
  24     uint32_t      desc_cksum;    // Checksum over image descriptor
  25     uint32_t      file_cksum;    // Checksum over image data
  26 };
  27
  28 struct fis_list {
  29         struct fis_image_desc *img;
  30         struct fis_list *next;
  31 };
  32
  33 static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
  34 module_param(directory, int, 0);
  35
  36 static inline int redboot_checksum(struct fis_image_desc *img)
  37 {
  38         /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
  39         return 1;
  40 }
  41
  42 static int parse_redboot_partitions(struct mtd_info *master,
  43                              struct mtd_partition **pparts,
  44                              unsigned long fis_origin)
  45 {
  46         int nrparts = 0;
  47         struct fis_image_desc *buf;
  48         struct mtd_partition *parts;
  49         struct fis_list *fl = NULL, *tmp_fl;
  50         int ret, i;
  51         size_t retlen;
  52         char *names;
  53         char *nullname;
  54         int namelen = 0;
  55         int nulllen = 0;
  56         int numslots;
  57         unsigned long offset;
  58 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
  59         static char nullstring[] = "unallocated";
  60 #endif
  61
  62         if ( directory < 0 ) {
  63                 offset = master->size + directory * master->erasesize;
  64                 while (master->block_isbad &&
  65                        master->block_isbad(master, offset)) {
  66                         if (!offset) {
  67                         nogood:
  68                                 printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
  69                                 return -EIO;
  70                         }
  71                         offset -= master->erasesize;
  72                 }
  73         } else {
  74                 offset = directory * master->erasesize;
  75                 while (master->block_isbad &&
  76                        master->block_isbad(master, offset)) {
  77                         offset += master->erasesize;
  78                         if (offset == master->size)
  79                                 goto nogood;
  80                 }
  81         }
  82         buf = vmalloc(master->erasesize);
  83
  84         if (!buf)
  85                 return -ENOMEM;
  86
  87         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
  88                master->name, offset);
  89
  90         ret = master->read(master, offset,
  91                            master->erasesize, &retlen, (void *)buf);
  92
  93         if (ret)
  94                 goto out;
  95
  96         if (retlen != master->erasesize) {
  97                 ret = -EIO;
  98                 goto out;
  99         }
 100
 101         numslots = (master->erasesize / sizeof(struct fis_image_desc));
 102         for (i = 0; i < numslots; i++) {
 103                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
 104                         /* This is apparently the FIS directory entry for the
 105                          * FIS directory itself.  The FIS directory size is
 106                          * one erase block; if the buf[i].size field is
 107                          * swab32(erasesize) then we know we are looking at
 108                          * a byte swapped FIS directory - swap all the entries!
 109                          * (NOTE: this is 'size' not 'data_length'; size is
 110                          * the full size of the entry.)
 111                          */
 112
 113                         /* RedBoot can combine the FIS directory and
 114                            config partitions into a single eraseblock;
 115                            we assume wrong-endian if either the swapped
 116                            'size' matches the eraseblock size precisely,
 117                            or if the swapped size actually fits in an
 118                            eraseblock while the unswapped size doesn't. */
 119                         if (swab32(buf[i].size) == master->erasesize ||
 120                             (buf[i].size > master->erasesize
 121                              && swab32(buf[i].size) < master->erasesize)) {
 122                                 int j;
 123                                 /* Update numslots based on actual FIS directory size */
 124                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 125                                 for (j = 0; j < numslots; ++j) {
 126
 127                                         /* A single 0xff denotes a deleted entry.
 128                                          * Two of them in a row is the end of the table.
 129                                          */
 130                                         if (buf[j].name[0] == 0xff) {
 131                                                 if (buf[j].name[1] == 0xff) {
 132                                                         break;
 133                                                 } else {
 134                                                         continue;
 135                                                 }
 136                                         }
 137
 138                                         /* The unsigned long fields were written with the
 139                                          * wrong byte sex, name and pad have no byte sex.
 140                                          */
 141                                         swab32s(&buf[j].flash_base);
 142                                         swab32s(&buf[j].mem_base);
 143                                         swab32s(&buf[j].size);
 144                                         swab32s(&buf[j].entry_point);
 145                                         swab32s(&buf[j].data_length);
 146                                         swab32s(&buf[j].desc_cksum);
 147                                         swab32s(&buf[j].file_cksum);
 148                                 }
 149                         } else if (buf[i].size < master->erasesize) {
 150                                 /* Update numslots based on actual FIS directory size */
 151                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 152                         }
 153                         break;
 154                 }
 155         }
 156         if (i == numslots) {
 157                 /* Didn't find it */
 158                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 159                        master->name);
 160                 ret = 0;
 161                 goto out;
 162         }
 163
 164         for (i = 0; i < numslots; i++) {
 165                 struct fis_list *new_fl, **prev;
 166
 167                 if (buf[i].name[0] == 0xff) {
 168                         if (buf[i].name[1] == 0xff) {
 169                                 break;
 170                         } else {
 171                                 continue;
 172                         }
 173                 }
 174                 if (!redboot_checksum(&buf[i]))
 175                         break;
 176
 177                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 178                 namelen += strlen(buf[i].name)+1;
 179                 if (!new_fl) {
 180                         ret = -ENOMEM;
 181                         goto out;
 182                 }
 183                 new_fl->img = &buf[i];
 184                 if (fis_origin) {
 185                         buf[i].flash_base -= fis_origin;
 186                 } else {
 187                         buf[i].flash_base &= master->size-1;
 188                 }
 189
 190                 /* I'm sure the JFFS2 code has done me permanent damage.
 191                  * I now think the following is _normal_
 192                  */
 193                 prev = &fl;
 194                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 195                         prev = &(*prev)->next;
 196                 new_fl->next = *prev;
 197                 *prev = new_fl;
 198
 199                 nrparts++;
 200         }
 201 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 202         if (fl->img->flash_base) {
 203                 nrparts++;
 204                 nulllen = sizeof(nullstring);
 205         }
 206
 207         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 208                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 209                         nrparts++;
 210                         nulllen = sizeof(nullstring);
 211                 }
 212         }
 213 #endif
 214         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 215
 216         if (!parts) {
 217                 ret = -ENOMEM;
 218                 goto out;
 219         }
 220
 221         nullname = (char *)&parts[nrparts];
 222 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 223         if (nulllen > 0) {
 224                 strcpy(nullname, nullstring);
 225         }
 226 #endif
 227         names = nullname + nulllen;
 228
 229         i=0;
 230
 231 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 232         if (fl->img->flash_base) {
 233                parts[0].name = nullname;
 234                parts[0].size = fl->img->flash_base;
 235                parts[0].offset = 0;
 236                 i++;
 237         }
 238 #endif
 239         for ( ; i<nrparts; i++) {
 240                 parts[i].size = fl->img->size;
 241                 parts[i].offset = fl->img->flash_base;
 242                 parts[i].name = names;
 243
 244                 strcpy(names, fl->img->name);
 245 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 246                 if (!memcmp(names, "RedBoot", 8) ||
 247                                 !memcmp(names, "RedBoot config", 15) ||
 248                                 !memcmp(names, "FIS directory", 14)) {
 249                         parts[i].mask_flags = MTD_WRITEABLE;
 250                 }
 251 #endif
 252                 names += strlen(names)+1;
 253
 254 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 255                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 256                         i++;
 257                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 258                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 259                         parts[i].name = nullname;
 260                 }
 261 #endif
 262                 tmp_fl = fl;
 263                 fl = fl->next;
 264                 kfree(tmp_fl);
 265         }
 266         ret = nrparts;
 267         *pparts = parts;
 268  out:
 269         while (fl) {
 270                 struct fis_list *old = fl;
 271                 fl = fl->next;
 272                 kfree(old);
 273         }
 274         vfree(buf);
 275         return ret;
 276 }
 277
 278 static struct mtd_part_parser redboot_parser = {
 279         .owner = THIS_MODULE,
 280         .parse_fn = parse_redboot_partitions,
 281         .name = "RedBoot",
 282 };
 283
 284 static int __init redboot_parser_init(void)
 285 {
 286         return register_mtd_parser(&redboot_parser);
 287 }
 288
 289 static void __exit redboot_parser_exit(void)
 290 {
 291         deregister_mtd_parser(&redboot_parser);
 292 }
 293
 294 module_init(redboot_parser_init);
 295 module_exit(redboot_parser_exit);
 296
 297 MODULE_LICENSE("GPL");
 298 MODULE_AUTHOR("Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>");
 299 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");