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         struct device_node *npart;
  49         u32 dirblock;
  50         int ret;
  51
  52         np = mtd_get_of_node(master);
  53         if (!np)
  54                 return;
  55
  56         npart = of_get_child_by_name(np, "partitions");
  57         if (!npart)
  58                 return;
  59
  60         ret = of_property_read_u32(npart, "fis-index-block", &dirblock);
  61         of_node_put(npart);
  62         if (ret)
  63                 return;
  64
  65         /*
  66          * Assign the block found in the device tree to the local
  67          * directory block pointer.
  68          */
  69         directory = dirblock;
  70 }
  71
  72 static int parse_redboot_partitions(struct mtd_info *master,
  73                                     const struct mtd_partition **pparts,
  74                                     struct mtd_part_parser_data *data)
  75 {
  76         int nrparts = 0;
  77         struct fis_image_desc *buf;
  78         struct mtd_partition *parts;
  79         struct fis_list *fl = NULL, *tmp_fl;
  80         int ret, i;
  81         size_t retlen;
  82         char *names;
  83         char *nullname;
  84         int namelen = 0;
  85         int nulllen = 0;
  86         int numslots;
  87         unsigned long offset;
  88 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
  89         static char nullstring[] = "unallocated";
  90 #endif
  91
  92         parse_redboot_of(master);
  93
  94         if ( directory < 0 ) {
  95                 offset = master->size + directory * master->erasesize;
  96                 while (mtd_block_isbad(master, offset)) {
  97                         if (!offset) {
  98                         nogood:
  99                                 printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
 100                                 return -EIO;
 101                         }
 102                         offset -= master->erasesize;
 103                 }
 104         } else {
 105                 offset = directory * master->erasesize;
 106                 while (mtd_block_isbad(master, offset)) {
 107                         offset += master->erasesize;
 108                         if (offset == master->size)
 109                                 goto nogood;
 110                 }
 111         }
 112         buf = vmalloc(master->erasesize);
 113
 114         if (!buf)
 115                 return -ENOMEM;
 116
 117         printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
 118                master->name, offset);
 119
 120         ret = mtd_read(master, offset, master->erasesize, &retlen,
 121                        (void *)buf);
 122
 123         if (ret)
 124                 goto out;
 125
 126         if (retlen != master->erasesize) {
 127                 ret = -EIO;
 128                 goto out;
 129         }
 130
 131         numslots = (master->erasesize / sizeof(struct fis_image_desc));
 132         for (i = 0; i < numslots; i++) {
 133                 if (!memcmp(buf[i].name, "FIS directory", 14)) {
 134                         /* This is apparently the FIS directory entry for the
 135                          * FIS directory itself.  The FIS directory size is
 136                          * one erase block; if the buf[i].size field is
 137                          * swab32(erasesize) then we know we are looking at
 138                          * a byte swapped FIS directory - swap all the entries!
 139                          * (NOTE: this is 'size' not 'data_length'; size is
 140                          * the full size of the entry.)
 141                          */
 142
 143                         /* RedBoot can combine the FIS directory and
 144                            config partitions into a single eraseblock;
 145                            we assume wrong-endian if either the swapped
 146                            'size' matches the eraseblock size precisely,
 147                            or if the swapped size actually fits in an
 148                            eraseblock while the unswapped size doesn't. */
 149                         if (swab32(buf[i].size) == master->erasesize ||
 150                             (buf[i].size > master->erasesize
 151                              && swab32(buf[i].size) < master->erasesize)) {
 152                                 int j;
 153                                 /* Update numslots based on actual FIS directory size */
 154                                 numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 155                                 for (j = 0; j < numslots; ++j) {
 156
 157                                         /* A single 0xff denotes a deleted entry.
 158                                          * Two of them in a row is the end of the table.
 159                                          */
 160                                         if (buf[j].name[0] == 0xff) {
 161                                                 if (buf[j].name[1] == 0xff) {
 162                                                         break;
 163                                                 } else {
 164                                                         continue;
 165                                                 }
 166                                         }
 167
 168                                         /* The unsigned long fields were written with the
 169                                          * wrong byte sex, name and pad have no byte sex.
 170                                          */
 171                                         swab32s(&buf[j].flash_base);
 172                                         swab32s(&buf[j].mem_base);
 173                                         swab32s(&buf[j].size);
 174                                         swab32s(&buf[j].entry_point);
 175                                         swab32s(&buf[j].data_length);
 176                                         swab32s(&buf[j].desc_cksum);
 177                                         swab32s(&buf[j].file_cksum);
 178                                 }
 179                         } else if (buf[i].size < master->erasesize) {
 180                                 /* Update numslots based on actual FIS directory size */
 181                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 182                         }
 183                         break;
 184                 }
 185         }
 186         if (i == numslots) {
 187                 /* Didn't find it */
 188                 printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 189                        master->name);
 190                 ret = 0;
 191                 goto out;
 192         }
 193
 194         for (i = 0; i < numslots; i++) {
 195                 struct fis_list *new_fl, **prev;
 196
 197                 if (buf[i].name[0] == 0xff) {
 198                         if (buf[i].name[1] == 0xff) {
 199                                 break;
 200                         } else {
 201                                 continue;
 202                         }
 203                 }
 204                 if (!redboot_checksum(&buf[i]))
 205                         break;
 206
 207                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 208                 namelen += strlen(buf[i].name)+1;
 209                 if (!new_fl) {
 210                         ret = -ENOMEM;
 211                         goto out;
 212                 }
 213                 new_fl->img = &buf[i];
 214                 if (data && data->origin)
 215                         buf[i].flash_base -= data->origin;
 216                 else
 217                         buf[i].flash_base &= master->size-1;
 218
 219                 /* I'm sure the JFFS2 code has done me permanent damage.
 220                  * I now think the following is _normal_
 221                  */
 222                 prev = &fl;
 223                 while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 224                         prev = &(*prev)->next;
 225                 new_fl->next = *prev;
 226                 *prev = new_fl;
 227
 228                 nrparts++;
 229         }
 230 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 231         if (fl->img->flash_base) {
 232                 nrparts++;
 233                 nulllen = sizeof(nullstring);
 234         }
 235
 236         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 237                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 238                         nrparts++;
 239                         nulllen = sizeof(nullstring);
 240                 }
 241         }
 242 #endif
 243         parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 244
 245         if (!parts) {
 246                 ret = -ENOMEM;
 247                 goto out;
 248         }
 249
 250         nullname = (char *)&parts[nrparts];
 251 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 252         if (nulllen > 0) {
 253                 strcpy(nullname, nullstring);
 254         }
 255 #endif
 256         names = nullname + nulllen;
 257
 258         i=0;
 259
 260 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 261         if (fl->img->flash_base) {
 262                parts[0].name = nullname;
 263                parts[0].size = fl->img->flash_base;
 264                parts[0].offset = 0;
 265                 i++;
 266         }
 267 #endif
 268         for ( ; i<nrparts; i++) {
 269                 parts[i].size = fl->img->size;
 270                 parts[i].offset = fl->img->flash_base;
 271                 parts[i].name = names;
 272
 273                 strcpy(names, fl->img->name);
 274 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 275                 if (!memcmp(names, "RedBoot", 8) ||
 276                                 !memcmp(names, "RedBoot config", 15) ||
 277                                 !memcmp(names, "FIS directory", 14)) {
 278                         parts[i].mask_flags = MTD_WRITEABLE;
 279                 }
 280 #endif
 281                 names += strlen(names)+1;
 282
 283 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 284                 if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 285                         i++;
 286                         parts[i].offset = parts[i-1].size + parts[i-1].offset;
 287                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 288                         parts[i].name = nullname;
 289                 }
 290 #endif
 291                 tmp_fl = fl;
 292                 fl = fl->next;
 293                 kfree(tmp_fl);
 294         }
 295         ret = nrparts;
 296         *pparts = parts;
 297  out:
 298         while (fl) {
 299                 struct fis_list *old = fl;
 300                 fl = fl->next;
 301                 kfree(old);
 302         }
 303         vfree(buf);
 304         return ret;
 305 }
 306
 307 static const struct of_device_id mtd_parser_redboot_of_match_table[] = {
 308         { .compatible = "redboot-fis" },
 309         {},
 310 };
 311 MODULE_DEVICE_TABLE(of, mtd_parser_redboot_of_match_table);
 312
 313 static struct mtd_part_parser redboot_parser = {
 314         .parse_fn = parse_redboot_partitions,
 315         .name = "RedBoot",
 316         .of_match_table = mtd_parser_redboot_of_match_table,
 317 };
 318 module_mtd_part_parser(redboot_parser);
 319
 320 /* mtd parsers will request the module by parser name */
 321 MODULE_ALIAS("RedBoot");
 322 MODULE_LICENSE("GPL");
 323 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 324 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");