LXR linux/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
  19struct 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
  31struct fis_list {
  32        struct fis_image_desc *img;
  33        struct fis_list *next;
  34};
  35
  36static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
  37module_param(directory, int, 0);
  38
  39static 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
  45static 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
  71static 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) {
  97nogood:
  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
 305static const struct of_device_id mtd_parser_redboot_of_match_table[] = {
 306        { .compatible = "redboot-fis" },
 307        {},
 308};
 309MODULE_DEVICE_TABLE(of, mtd_parser_redboot_of_match_table);
 310
 311static 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};
 316module_mtd_part_parser(redboot_parser);
 317
 318/* mtd parsers will request the module by parser name */
 319MODULE_ALIAS("RedBoot");
 320MODULE_LICENSE("GPL");
 321MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 322MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");
 323