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         buf = vmalloc(master->erasesize);
  63
  64         if (!buf)
  65                 return -ENOMEM;
  66
  67         if ( directory < 0 )
  68                 offset = master->size + directory*master->erasesize;
  69         else
  70                 offset = directory*master->erasesize;
  71
  72         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
  73                master->name, offset);
  74
  75         ret = master->read(master, offset,
  76                            master->erasesize, &retlen, (void *)buf);
  77
  78         if (ret)
  79                 goto out;
  80
  81         if (retlen != master->erasesize) {
  82                 ret = -EIO;
  83                 goto out;
  84         }
  85
  86         numslots = (master->erasesize / sizeof(struct fis_image_desc));
  87         for (i = 0; i < numslots; i++) {
  88                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
  89                         /* This is apparently the FIS directory entry for the
  90                          * FIS directory itself.  The FIS directory size is
  91                          * one erase block; if the buf[i].size field is
  92                          * swab32(erasesize) then we know we are looking at
  93                          * a byte swapped FIS directory - swap all the entries!
  94                          * (NOTE: this is 'size' not 'data_length'; size is
  95                          * the full size of the entry.)
  96                          */
  97
  98                         /* RedBoot can combine the FIS directory and
  99                            config partitions into a single eraseblock;
 100                            we assume wrong-endian if either the swapped
 101                            'size' matches the eraseblock size precisely,
 102                            or if the swapped size actually fits in an
 103                            eraseblock while the unswapped size doesn't. */
 104                         if (swab32(buf[i].size) == master->erasesize ||
 105                             (buf[i].size > master->erasesize
 106                              && swab32(buf[i].size) < master->erasesize)) {
 107                                 int j;
 108                                 /* Update numslots based on actual FIS directory size */
 109                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 110                                 for (j = 0; j < numslots; ++j) {
 111
 112                                         /* A single 0xff denotes a deleted entry.
 113                                          * Two of them in a row is the end of the table.
 114                                          */
 115                                         if (buf[j].name[0] == 0xff) {
 116                                                 if (buf[j].name[1] == 0xff) {
 117                                                         break;
 118                                                 } else {
 119                                                         continue;
 120                                                 }
 121                                         }
 122
 123                                         /* The unsigned long fields were written with the
 124                                          * wrong byte sex, name and pad have no byte sex.
 125                                          */
 126                                         swab32s(&buf[j].flash_base);
 127                                         swab32s(&buf[j].mem_base);
 128                                         swab32s(&buf[j].size);
 129                                         swab32s(&buf[j].entry_point);
 130                                         swab32s(&buf[j].data_length);
 131                                         swab32s(&buf[j].desc_cksum);
 132                                         swab32s(&buf[j].file_cksum);
 133                                 }
 134                         } else if (buf[i].size < master->erasesize) {
 135                                 /* Update numslots based on actual FIS directory size */
 136                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 137                         }
 138                         break;
 139                 }
 140         }
 141         if (i == numslots) {
 142                 /* Didn't find it */
 143                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 144                        master->name);
 145                 ret = 0;
 146                 goto out;
 147         }
 148
 149         for (i = 0; i < numslots; i++) {
 150                 struct fis_list *new_fl, **prev;
 151
 152                 if (buf[i].name[0] == 0xff) {
 153                         if (buf[i].name[1] == 0xff) {
 154                                 break;
 155                         } else {
 156                                 continue;
 157                         }
 158                 }
 159                 if (!redboot_checksum(&buf[i]))
 160                         break;
 161
 162                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 163                 namelen += strlen(buf[i].name)+1;
 164                 if (!new_fl) {
 165                         ret = -ENOMEM;
 166                         goto out;
 167                 }
 168                 new_fl->img = &buf[i];
 169                 if (fis_origin) {
 170                         buf[i].flash_base -= fis_origin;
 171                 } else {
 172                         buf[i].flash_base &= master->size-1;
 173                 }
 174
 175                 /* I'm sure the JFFS2 code has done me permanent damage.
 176                  * I now think the following is _normal_
 177                  */
 178                 prev = &fl;
 179                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 180                         prev = &(*prev)->next;
 181                 new_fl->next = *prev;
 182                 *prev = new_fl;
 183
 184                 nrparts++;
 185         }
 186 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 187         if (fl->img->flash_base) {
 188                 nrparts++;
 189                 nulllen = sizeof(nullstring);
 190         }
 191
 192         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 193                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 194                         nrparts++;
 195                         nulllen = sizeof(nullstring);
 196                 }
 197         }
 198 #endif
 199         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 200
 201         if (!parts) {
 202                 ret = -ENOMEM;
 203                 goto out;
 204         }
 205
 206         nullname = (char *)&parts[nrparts];
 207 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 208         if (nulllen > 0) {
 209                 strcpy(nullname, nullstring);
 210         }
 211 #endif
 212         names = nullname + nulllen;
 213
 214         i=0;
 215
 216 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 217         if (fl->img->flash_base) {
 218                parts[0].name = nullname;
 219                parts[0].size = fl->img->flash_base;
 220                parts[0].offset = 0;
 221                 i++;
 222         }
 223 #endif
 224         for ( ; i<nrparts; i++) {
 225                 parts[i].size = fl->img->size;
 226                 parts[i].offset = fl->img->flash_base;
 227                 parts[i].name = names;
 228
 229                 strcpy(names, fl->img->name);
 230 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 231                 if (!memcmp(names, "RedBoot", 8) ||
 232                                 !memcmp(names, "RedBoot config", 15) ||
 233                                 !memcmp(names, "FIS directory", 14)) {
 234                         parts[i].mask_flags = MTD_WRITEABLE;
 235                 }
 236 #endif
 237                 names += strlen(names)+1;
 238
 239 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 240                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 241                         i++;
 242                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 243                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 244                         parts[i].name = nullname;
 245                 }
 246 #endif
 247                 tmp_fl = fl;
 248                 fl = fl->next;
 249                 kfree(tmp_fl);
 250         }
 251         ret = nrparts;
 252         *pparts = parts;
 253  out:
 254         while (fl) {
 255                 struct fis_list *old = fl;
 256                 fl = fl->next;
 257                 kfree(old);
 258         }
 259         vfree(buf);
 260         return ret;
 261 }
 262
 263 static struct mtd_part_parser redboot_parser = {
 264         .owner = THIS_MODULE,
 265         .parse_fn = parse_redboot_partitions,
 266         .name = "RedBoot",
 267 };
 268
 269 static int __init redboot_parser_init(void)
 270 {
 271         return register_mtd_parser(&redboot_parser);
 272 }
 273
 274 static void __exit redboot_parser_exit(void)
 275 {
 276         deregister_mtd_parser(&redboot_parser);
 277 }
 278
 279 module_init(redboot_parser_init);
 280 module_exit(redboot_parser_exit);
 281
 282 MODULE_LICENSE("GPL");
 283 MODULE_AUTHOR("Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>");
 284 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");