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                         if (swab32(buf[i].size) == master->erasesize) {
  98                                 int j;
  99                                 for (j = 0; j < numslots; ++j) {
 100
 101                                         /* A single 0xff denotes a deleted entry.
 102                                          * Two of them in a row is the end of the table.
 103                                          */
 104                                         if (buf[j].name[0] == 0xff) {
 105                                                 if (buf[j].name[1] == 0xff) {
 106                                                         break;
 107                                                 } else {
 108                                                         continue;
 109                                                 }
 110                                         }
 111
 112                                         /* The unsigned long fields were written with the
 113                                          * wrong byte sex, name and pad have no byte sex.
 114                                          */
 115                                         swab32s(&buf[j].flash_base);
 116                                         swab32s(&buf[j].mem_base);
 117                                         swab32s(&buf[j].size);
 118                                         swab32s(&buf[j].entry_point);
 119                                         swab32s(&buf[j].data_length);
 120                                         swab32s(&buf[j].desc_cksum);
 121                                         swab32s(&buf[j].file_cksum);
 122                                 }
 123                         }
 124                         break;
 125                 } else {
 126                         /* re-calculate of real numslots */
 127                         numslots = buf[i].size / sizeof(struct fis_image_desc);
 128                 }
 129         }
 130         if (i == numslots) {
 131                 /* Didn't find it */
 132                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 133                        master->name);
 134                 ret = 0;
 135                 goto out;
 136         }
 137
 138         for (i = 0; i < numslots; i++) {
 139                 struct fis_list *new_fl, **prev;
 140
 141                 if (buf[i].name[0] == 0xff) {
 142                         if (buf[i].name[1] == 0xff) {
 143                                 break;
 144                         } else {
 145                                 continue;
 146                         }
 147                 }
 148                 if (!redboot_checksum(&buf[i]))
 149                         break;
 150
 151                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 152                 namelen += strlen(buf[i].name)+1;
 153                 if (!new_fl) {
 154                         ret = -ENOMEM;
 155                         goto out;
 156                 }
 157                 new_fl->img = &buf[i];
 158                 if (fis_origin) {
 159                         buf[i].flash_base -= fis_origin;
 160                 } else {
 161                         buf[i].flash_base &= master->size-1;
 162                 }
 163
 164                 /* I'm sure the JFFS2 code has done me permanent damage.
 165                  * I now think the following is _normal_
 166                  */
 167                 prev = &fl;
 168                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 169                         prev = &(*prev)->next;
 170                 new_fl->next = *prev;
 171                 *prev = new_fl;
 172
 173                 nrparts++;
 174         }
 175 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 176         if (fl->img->flash_base) {
 177                 nrparts++;
 178                 nulllen = sizeof(nullstring);
 179         }
 180
 181         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 182                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 183                         nrparts++;
 184                         nulllen = sizeof(nullstring);
 185                 }
 186         }
 187 #endif
 188         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 189
 190         if (!parts) {
 191                 ret = -ENOMEM;
 192                 goto out;
 193         }
 194
 195         nullname = (char *)&parts[nrparts];
 196 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 197         if (nulllen > 0) {
 198                 strcpy(nullname, nullstring);
 199         }
 200 #endif
 201         names = nullname + nulllen;
 202
 203         i=0;
 204
 205 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 206         if (fl->img->flash_base) {
 207                parts[0].name = nullname;
 208                parts[0].size = fl->img->flash_base;
 209                parts[0].offset = 0;
 210                 i++;
 211         }
 212 #endif
 213         for ( ; i<nrparts; i++) {
 214                 parts[i].size = fl->img->size;
 215                 parts[i].offset = fl->img->flash_base;
 216                 parts[i].name = names;
 217
 218                 strcpy(names, fl->img->name);
 219 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 220                 if (!memcmp(names, "RedBoot", 8) ||
 221                                 !memcmp(names, "RedBoot config", 15) ||
 222                                 !memcmp(names, "FIS directory", 14)) {
 223                         parts[i].mask_flags = MTD_WRITEABLE;
 224                 }
 225 #endif
 226                 names += strlen(names)+1;
 227
 228 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 229                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 230                         i++;
 231                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 232                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 233                         parts[i].name = nullname;
 234                 }
 235 #endif
 236                 tmp_fl = fl;
 237                 fl = fl->next;
 238                 kfree(tmp_fl);
 239         }
 240         ret = nrparts;
 241         *pparts = parts;
 242  out:
 243         while (fl) {
 244                 struct fis_list *old = fl;
 245                 fl = fl->next;
 246                 kfree(old);
 247         }
 248         vfree(buf);
 249         return ret;
 250 }
 251
 252 static struct mtd_part_parser redboot_parser = {
 253         .owner = THIS_MODULE,
 254         .parse_fn = parse_redboot_partitions,
 255         .name = "RedBoot",
 256 };
 257
 258 static int __init redboot_parser_init(void)
 259 {
 260         return register_mtd_parser(&redboot_parser);
 261 }
 262
 263 static void __exit redboot_parser_exit(void)
 264 {
 265         deregister_mtd_parser(&redboot_parser);
 266 }
 267
 268 module_init(redboot_parser_init);
 269 module_exit(redboot_parser_exit);
 270
 271 MODULE_LICENSE("GPL");
 272 MODULE_AUTHOR("Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>");
 273 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");