drivers/mtd/redboot.c

   1 /*
   2  * $Id: redboot.c,v 1.19 2005/12/01 10:03:51 dwmw2 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     unsigned long flash_base;    // Address within FLASH of image
  19     unsigned long mem_base;      // Address in memory where it executes
  20     unsigned long size;          // Length of image
  21     unsigned long entry_point;   // Execution entry point
  22     unsigned long data_length;   // Length of actual data
  23     unsigned char _pad[256-(16+7*sizeof(unsigned long))];
  24     unsigned long desc_cksum;    // Checksum over image descriptor
  25     unsigned long 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 && buf[j].name[0] != 0xff; ++j) {
 100                                         /* The unsigned long fields were written with the
 101                                          * wrong byte sex, name and pad have no byte sex.
 102                                          */
 103                                         swab32s(&buf[j].flash_base);
 104                                         swab32s(&buf[j].mem_base);
 105                                         swab32s(&buf[j].size);
 106                                         swab32s(&buf[j].entry_point);
 107                                         swab32s(&buf[j].data_length);
 108                                         swab32s(&buf[j].desc_cksum);
 109                                         swab32s(&buf[j].file_cksum);
 110                                 }
 111                         }
 112                         break;
 113                 }
 114         }
 115         if (i == numslots) {
 116                 /* Didn't find it */
 117                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 118                        master->name);
 119                 ret = 0;
 120                 goto out;
 121         }
 122
 123         for (i = 0; i < numslots; i++) {
 124                 struct fis_list *new_fl, **prev;
 125
 126                 if (buf[i].name[0] == 0xff)
 127                         continue;
 128                 if (!redboot_checksum(&buf[i]))
 129                         break;
 130
 131                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 132                 namelen += strlen(buf[i].name)+1;
 133                 if (!new_fl) {
 134                         ret = -ENOMEM;
 135                         goto out;
 136                 }
 137                 new_fl->img = &buf[i];
 138                 if (fis_origin) {
 139                         buf[i].flash_base -= fis_origin;
 140                 } else {
 141                         buf[i].flash_base &= master->size-1;
 142                 }
 143
 144                 /* I'm sure the JFFS2 code has done me permanent damage.
 145                  * I now think the following is _normal_
 146                  */
 147                 prev = &fl;
 148                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 149                         prev = &(*prev)->next;
 150                 new_fl->next = *prev;
 151                 *prev = new_fl;
 152
 153                 nrparts++;
 154         }
 155 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 156         if (fl->img->flash_base) {
 157                 nrparts++;
 158                 nulllen = sizeof(nullstring);
 159         }
 160
 161         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 162                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 163                         nrparts++;
 164                         nulllen = sizeof(nullstring);
 165                 }
 166         }
 167 #endif
 168         parts = kmalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 169
 170         if (!parts) {
 171                 ret = -ENOMEM;
 172                 goto out;
 173         }
 174
 175         memset(parts, 0, sizeof(*parts)*nrparts + nulllen + namelen);
 176
 177         nullname = (char *)&parts[nrparts];
 178 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 179         if (nulllen > 0) {
 180                 strcpy(nullname, nullstring);
 181         }
 182 #endif
 183         names = nullname + nulllen;
 184
 185         i=0;
 186
 187 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 188         if (fl->img->flash_base) {
 189                parts[0].name = nullname;
 190                parts[0].size = fl->img->flash_base;
 191                parts[0].offset = 0;
 192                 i++;
 193         }
 194 #endif
 195         for ( ; i<nrparts; i++) {
 196                 parts[i].size = fl->img->size;
 197                 parts[i].offset = fl->img->flash_base;
 198                 parts[i].name = names;
 199
 200                 strcpy(names, fl->img->name);
 201 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 202                 if (!memcmp(names, "RedBoot", 8) ||
 203                                 !memcmp(names, "RedBoot config", 15) ||
 204                                 !memcmp(names, "FIS directory", 14)) {
 205                         parts[i].mask_flags = MTD_WRITEABLE;
 206                 }
 207 #endif
 208                 names += strlen(names)+1;
 209
 210 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 211                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 212                         i++;
 213                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 214                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 215                         parts[i].name = nullname;
 216                 }
 217 #endif
 218                 tmp_fl = fl;
 219                 fl = fl->next;
 220                 kfree(tmp_fl);
 221         }
 222         ret = nrparts;
 223         *pparts = parts;
 224  out:
 225         while (fl) {
 226                 struct fis_list *old = fl;
 227                 fl = fl->next;
 228                 kfree(old);
 229         }
 230         vfree(buf);
 231         return ret;
 232 }
 233
 234 static struct mtd_part_parser redboot_parser = {
 235         .owner = THIS_MODULE,
 236         .parse_fn = parse_redboot_partitions,
 237         .name = "RedBoot",
 238 };
 239
 240 static int __init redboot_parser_init(void)
 241 {
 242         return register_mtd_parser(&redboot_parser);
 243 }
 244
 245 static void __exit redboot_parser_exit(void)
 246 {
 247         deregister_mtd_parser(&redboot_parser);
 248 }
 249
 250 module_init(redboot_parser_init);
 251 module_exit(redboot_parser_exit);
 252
 253 MODULE_LICENSE("GPL");
 254 MODULE_AUTHOR("Red Hat, Inc. - David Woodhouse <dwmw2@cambridge.redhat.com>");
 255 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");