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    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
  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        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
  66static 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
 301static const struct of_device_id mtd_parser_redboot_of_match_table[] = {
 302        { .compatible = "redboot-fis" },
 303        {},
 304};
 305MODULE_DEVICE_TABLE(of, mtd_parser_redboot_of_match_table);
 306
 307static 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};
 312module_mtd_part_parser(redboot_parser);
 313
 314/* mtd parsers will request the module by parser name */
 315MODULE_ALIAS("RedBoot");
 316MODULE_LICENSE("GPL");
 317MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 318MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");
 319