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         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                                 pr_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         pr_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                                         /* A single 0xff denotes a deleted entry.
 157                                          * Two of them in a row is the end of the table.
 158                                          */
 159                                         if (buf[j].name[0] == 0xff) {
 160                                                 if (buf[j].name[1] == 0xff) {
 161                                                         break;
 162                                                 } else {
 163                                                         continue;
 164                                                 }
 165                                         }
 166
 167                                         /* The unsigned long fields were written with the
 168                                          * wrong byte sex, name and pad have no byte sex.
 169                                          */
 170                                         swab32s(&buf[j].flash_base);
 171                                         swab32s(&buf[j].mem_base);
 172                                         swab32s(&buf[j].size);
 173                                         swab32s(&buf[j].entry_point);
 174                                         swab32s(&buf[j].data_length);
 175                                         swab32s(&buf[j].desc_cksum);
 176                                         swab32s(&buf[j].file_cksum);
 177                                 }
 178                         } else if (buf[i].size < master->erasesize) {
 179                                 /* Update numslots based on actual FIS directory size */
 180                                 numslots = buf[i].size / sizeof(struct fis_image_desc);
 181                         }
 182                         break;
 183                 }
 184         }
 185         if (i == numslots) {
 186                 /* Didn't find it */
 187                 pr_notice("No RedBoot partition table detected in %s\n",
 188                           master->name);
 189                 ret = 0;
 190                 goto out;
 191         }
 192
 193         for (i = 0; i < numslots; i++) {
 194                 struct fis_list *new_fl, **prev;
 195
 196                 if (buf[i].name[0] == 0xff) {
 197                         if (buf[i].name[1] == 0xff) {
 198                                 break;
 199                         } else {
 200                                 continue;
 201                         }
 202                 }
 203                 if (!redboot_checksum(&buf[i]))
 204                         break;
 205
 206                 new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 207                 namelen += strlen(buf[i].name) + 1;
 208                 if (!new_fl) {
 209                         ret = -ENOMEM;
 210                         goto out;
 211                 }
 212                 new_fl->img = &buf[i];
 213                 if (data && data->origin)
 214                         buf[i].flash_base -= data->origin;
 215                 else
 216                         buf[i].flash_base &= master->size - 1;
 217
 218                 /* I'm sure the JFFS2 code has done me permanent damage.
 219                  * I now think the following is _normal_
 220                  */
 221                 prev = &fl;
 222                 while (*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 223                         prev = &(*prev)->next;
 224                 new_fl->next = *prev;
 225                 *prev = new_fl;
 226
 227                 nrparts++;
 228         }
 229 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 230         if (fl->img->flash_base) {
 231                 nrparts++;
 232                 nulllen = sizeof(nullstring);
 233         }
 234
 235         for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 236                 if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 237                         nrparts++;
 238                         nulllen = sizeof(nullstring);
 239                 }
 240         }
 241 #endif
 242         parts = kzalloc(sizeof(*parts) * nrparts + nulllen + namelen, GFP_KERNEL);
 243
 244         if (!parts) {
 245                 ret = -ENOMEM;
 246                 goto out;
 247         }
 248
 249         nullname = (char *)&parts[nrparts];
 250 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 251         if (nulllen > 0)
 252                 strcpy(nullname, nullstring);
 253 #endif
 254         names = nullname + nulllen;
 255
 256         i = 0;
 257
 258 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 259         if (fl->img->flash_base) {
 260                 parts[0].name = nullname;
 261                 parts[0].size = fl->img->flash_base;
 262                 parts[0].offset = 0;
 263                 i++;
 264         }
 265 #endif
 266         for ( ; i < nrparts; i++) {
 267                 parts[i].size = fl->img->size;
 268                 parts[i].offset = fl->img->flash_base;
 269                 parts[i].name = names;
 270
 271                 strcpy(names, fl->img->name);
 272 #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 273                 if (!memcmp(names, "RedBoot", 8) ||
 274                     !memcmp(names, "RedBoot config", 15) ||
 275                     !memcmp(names, "FIS directory", 14)) {
 276                         parts[i].mask_flags = MTD_WRITEABLE;
 277                 }
 278 #endif
 279                 names += strlen(names) + 1;
 280
 281 #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 282                 if (fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 283                         i++;
 284                         parts[i].offset = parts[i - 1].size + parts[i - 1].offset;
 285                         parts[i].size = fl->next->img->flash_base - parts[i].offset;
 286                         parts[i].name = nullname;
 287                 }
 288 #endif
 289                 tmp_fl = fl;
 290                 fl = fl->next;
 291                 kfree(tmp_fl);
 292         }
 293         ret = nrparts;
 294         *pparts = parts;
 295  out:
 296         while (fl) {
 297                 struct fis_list *old = fl;
 298
 299                 fl = fl->next;
 300                 kfree(old);
 301         }
 302         vfree(buf);
 303         return ret;
 304 }
 305
 306 static const struct of_device_id mtd_parser_redboot_of_match_table[] = {
 307         { .compatible = "redboot-fis" },
 308         {},
 309 };
 310 MODULE_DEVICE_TABLE(of, mtd_parser_redboot_of_match_table);
 311
 312 static struct mtd_part_parser redboot_parser = {
 313         .parse_fn = parse_redboot_partitions,
 314         .name = "RedBoot",
 315         .of_match_table = mtd_parser_redboot_of_match_table,
 316 };
 317 module_mtd_part_parser(redboot_parser);
 318
 319 /* mtd parsers will request the module by parser name */
 320 MODULE_ALIAS("RedBoot");
 321 MODULE_LICENSE("GPL");
 322 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 323 MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");