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