drivers/mtd/parsers/redboot.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Parse RedBoot-style Flash Image System (FIS) tables and
   4  * produce a Linux partition array to match.
   5  *
   6  * Copyright © 2001      Red Hat UK Limited
   7  * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12 #include <linux/init.h>
  13 #include <linux/vmalloc.h>
  14 #include <linux/of.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/mtd/partitions.h>
  17 #include <linux/module.h>
  18
  19 struct fis_image_desc {
  20     unsigned char name[16];      // Null terminated name
  21     uint32_t      flash_base;    // Address within FLASH of image
  22     uint32_t      mem_base;      // Address in memory where it executes
  23     uint32_t      size;          // Length of image
  24     uint32_t      entry_point;   // Execution entry point
  25     uint32_t      data_length;   // Length of actual data
  26     unsigned char _pad[256-(16+7*sizeof(uint32_t))];
  27     uint32_t      desc_cksum;    // Checksum over image descriptor
  28     uint32_t      file_cksum;    // Checksum over image data
  29 };
  30
  31 struct fis_list {
  32         struct fis_image_desc *img;
  33         struct fis_list *next;
  34 };
  35
  36 static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
  37 module_param(directory, int, 0);
  38
  39 static inline int redboot_checksum(struct fis_image_desc *img)
  40 {
  41         /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
  42         return 1;
  43 }
  44
  45 static void parse_redboot_of(struct mtd_info *master)
  46 {
  47         struct device_node *np;
  48         u32 dirblock;
  49         int ret;
  50
  51         np = mtd_get_of_node(master);
  52         if (!np)
  53                 return;
  54
  55         ret = of_property_read_u32(np, "fis-index-block", &dirblock);
  56         if (ret)
  57                 return;
  58
  59         /*
  60          * Assign the block found in the device tree to the local
  61          * directory block pointer.
  62          */
  63         directory = dirblock;
  64 }
  65
  66 static int parse_redboot_partitions(struct mtd_info *master,
  67                                     const struct mtd_partition **pparts,
  68                                     struct mtd_part_parser_data *data)
  69 {
  70         int nrparts = 0;
  71         struct fis_image_desc *buf;
  72         struct mtd_partition *parts;
  73         struct fis_list *fl = NULL, *tmp_fl;
  74         int ret, i;
  75         size_t retlen;
  76         char *names;
  77         char *nullname;
  78         int namelen = 0;
  79         int nulllen = 0;
  80         int numslots;
  81         unsigned long offset;
  82 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
  83         static char nullstring[] = "unallocated";
  84 #endif
  85
  86         parse_redboot_of(master);
  87
  88         if ( directory < 0 ) {
  89                 offset = master->size + directory * master->erasesize;
  90                 while (mtd_block_isbad(master, offset)) {
  91                         if (!offset) {
  92                         nogood:
  93                                 printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
  94                                 return -EIO;
  95                         }
  96                         offset -= master->erasesize;
  97                 }
  98         } else {
  99                 offset = directory * master->erasesize;
 100                 while (mtd_block_isbad(master, offset)) {
 101                         offset += master->erasesize;
 102                         if (offset == master->size)
 103                                 goto nogood;
 104                 }
 105         }
 106         buf = vmalloc(master->erasesize);
 107
 108         if (!buf)
 109                 return -ENOMEM;
 110
 111         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
 112                master->name, offset);
 113
 114         ret = mtd_read(master, offset, master->erasesize, &retlen,
 115                        (void *)buf);
 116
 117         if (ret)
 118                 goto out;
 119
 120         if (retlen != master->erasesize) {
 121                 ret = -EIO;
 122                 goto out;
 123         }
 124
 125         numslots = (master->erasesize / sizeof(struct fis_image_desc));
 126         for (i = 0; i < numslots; i++) {
 127                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
 128                         /* This is apparently the FIS directory entry for the
 129                          * FIS directory itself.  The FIS directory size is
 130                          * one erase block; if the buf[i].size field is
 131                          * swab32(erasesize) then we know we are looking at
 132                          * a byte swapped FIS directory - swap all the entries!
 133                          * (NOTE: this is 'size' not 'data_length'; size is
 134                          * the full size of the entry.)
 135                          */
 136
 137                         /* RedBoot can combine the FIS directory and
 138                            config partitions into a single eraseblock;
 139                            we assume wrong-endian if either the swapped
 140                            'size' matches the eraseblock size precisely,
 141                            or if the swapped size actually fits in an
 142                            eraseblock while the unswapped size doesn't. */
 143                         if (swab32(buf[i].size) == master->erasesize ||
 144                             (buf[i].size > master->erasesize
 145                              && swab32(buf[i].size) < master->erasesize)) {
 146                                 int j;
 147                                 /* Update numslots based on actual FIS directory size */
 148                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 149                                 for (j = 0; j < numslots; ++j) {
 150
 151                                         /* A single 0xff denotes a deleted entry.
 152                                          * Two of them in a row is the end of the table.
 153                                          */
 154                                         if (buf[j].name[0] == 0xff) {
 155                                                 if (buf[j].name[1] == 0xff) {
 156                                                         break;
 157                                                 } else {
 158                                                         continue;
 159                                                 }
 160                                         }
 161
 162                                         /* The unsigned long fields were written with the
 163                                          * wrong byte sex, name and pad have no byte sex.
 164                                          */
 165                                         swab32s(&buf[j].flash_base);
 166                                         swab32s(&buf[j].mem_base);
 167                                         swab32s(&buf[j].size);
 168                                         swab32s(&buf[j].entry_point);
 169                                         swab32s(&buf[j].data_length);
 170                                         swab32s(&buf[j].desc_cksum);
 171                                         swab32s(&buf[j].file_cksum);
 172                                 }
 173                         } else if (buf[i].size < master->erasesize) {
 174                                 /* Update numslots based on actual FIS directory size */
 175                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 176                         }
 177                         break;
 178                 }
 179         }
 180         if (i == numslots) {
 181                 /* Didn't find it */
 182                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 183                        master->name);
 184                 ret = 0;
 185                 goto out;
 186         }
 187
 188         for (i = 0; i < numslots; i++) {
 189                 struct fis_list *new_fl, **prev;
 190
 191                 if (buf[i].name[0] == 0xff) {
 192                         if (buf[i].name[1] == 0xff) {
 193                                 break;
 194                         } else {
 195                                 continue;
 196                         }
 197                 }
 198                 if (!redboot_checksum(&buf[i]))
 199                         break;
 200
 201                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 202                 namelen += strlen(buf[i].name)+1;
 203                 if (!new_fl) {
 204                         ret = -ENOMEM;
 205                         goto out;
 206                 }
 207                 new_fl->img = &buf[i];
 208                 if (data && data->origin)
 209                         buf[i].flash_base -= data->origin;
 210                 else
 211                         buf[i].flash_base &= master->size-1;
 212
 213                 /* I'm sure the JFFS2 code has done me permanent damage.
 214                  * I now think the following is _normal_
 215                  */
 216                 prev = &fl;
 217                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 218                         prev = &(*prev)->next;
 219                 new_fl->next = *prev;
 220                 *prev = new_fl;
 221
 222                 nrparts++;
 223         }
 224 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 225         if (fl->img->flash_base) {
 226                 nrparts++;
 227                 nulllen = sizeof(nullstring);
 228         }
 229
 230         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 231                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 232                         nrparts++;
 233                         nulllen = sizeof(nullstring);
 234                 }
 235         }
 236 #endif
 237         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 238
 239         if (!parts) {
 240                 ret = -ENOMEM;
 241                 goto out;
 242         }
 243
 244         nullname = (char *)&parts[nrparts];
 245 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 246         if (nulllen > 0) {
 247                 strcpy(nullname, nullstring);
 248         }
 249 #endif
 250         names = nullname + nulllen;
 251
 252         i=0;
 253
 254 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 255         if (fl->img->flash_base) {
 256                parts[0].name = nullname;
 257                parts[0].size = fl->img->flash_base;
 258                parts[0].offset = 0;
 259                 i++;
 260         }
 261 #endif
 262         for ( ; i<nrparts; i++) {
 263                 parts[i].size = fl->img->size;
 264                 parts[i].offset = fl->img->flash_base;
 265                 parts[i].name = names;
 266
 267                 strcpy(names, fl->img->name);
 268 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 269                 if (!memcmp(names, "RedBoot", 8) ||
 270                                 !memcmp(names, "RedBoot config", 15) ||
 271                                 !memcmp(names, "FIS directory", 14)) {
 272                         parts[i].mask_flags = MTD_WRITEABLE;
 273                 }
 274 #endif
 275                 names += strlen(names)+1;
 276
 277 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 278                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 279                         i++;
 280                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 281                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 282                         parts[i].name = nullname;
 283                 }
 284 #endif
 285                 tmp_fl = fl;
 286                 fl = fl->next;
 287                 kfree(tmp_fl);
 288         }
 289         ret = nrparts;
 290         *pparts = parts;
 291  out:
 292         while (fl) {
 293                 struct fis_list *old = fl;
 294                 fl = fl->next;
 295                 kfree(old);
 296         }
 297         vfree(buf);
 298         return ret;
 299 }
 300
 301 static const struct of_device_id mtd_parser_redboot_of_match_table[] = {
 302         { .compatible = "redboot-fis" },
 303         {},
 304 };
 305 MODULE_DEVICE_TABLE(of, mtd_parser_redboot_of_match_table);
 306
 307 static struct mtd_part_parser redboot_parser = {
 308         .parse_fn = parse_redboot_partitions,
 309         .name = "RedBoot",
 310         .of_match_table = mtd_parser_redboot_of_match_table,
 311 };
 312 module_mtd_part_parser(redboot_parser);
 313
 314 /* mtd parsers will request the module by parser name */
 315 MODULE_ALIAS("RedBoot");
 316 MODULE_LICENSE("GPL");
 317 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 318 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");