linux/drivers/mtd/redboot.c
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   1/*
   2 * Parse RedBoot-style Flash Image System (FIS) tables and
   3 * produce a Linux partition array to match.
   4 *
   5 * Copyright © 2001      Red Hat UK Limited
   6 * Copyright © 2001-2010 David Woodhouse <dwmw2@infradead.org>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  21 *
  22 */
  23
  24#include <linux/kernel.h>
  25#include <linux/slab.h>
  26#include <linux/init.h>
  27#include <linux/vmalloc.h>
  28
  29#include <linux/mtd/mtd.h>
  30#include <linux/mtd/partitions.h>
  31#include <linux/module.h>
  32
  33struct fis_image_desc {
  34    unsigned char name[16];      // Null terminated name
  35    uint32_t      flash_base;    // Address within FLASH of image
  36    uint32_t      mem_base;      // Address in memory where it executes
  37    uint32_t      size;          // Length of image
  38    uint32_t      entry_point;   // Execution entry point
  39    uint32_t      data_length;   // Length of actual data
  40    unsigned char _pad[256-(16+7*sizeof(uint32_t))];
  41    uint32_t      desc_cksum;    // Checksum over image descriptor
  42    uint32_t      file_cksum;    // Checksum over image data
  43};
  44
  45struct fis_list {
  46        struct fis_image_desc *img;
  47        struct fis_list *next;
  48};
  49
  50static int directory = CONFIG_MTD_REDBOOT_DIRECTORY_BLOCK;
  51module_param(directory, int, 0);
  52
  53static inline int redboot_checksum(struct fis_image_desc *img)
  54{
  55        /* RedBoot doesn't actually write the desc_cksum field yet AFAICT */
  56        return 1;
  57}
  58
  59static int parse_redboot_partitions(struct mtd_info *master,
  60                                    struct mtd_partition **pparts,
  61                                    struct mtd_part_parser_data *data)
  62{
  63        int nrparts = 0;
  64        struct fis_image_desc *buf;
  65        struct mtd_partition *parts;
  66        struct fis_list *fl = NULL, *tmp_fl;
  67        int ret, i;
  68        size_t retlen;
  69        char *names;
  70        char *nullname;
  71        int namelen = 0;
  72        int nulllen = 0;
  73        int numslots;
  74        unsigned long offset;
  75#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
  76        static char nullstring[] = "unallocated";
  77#endif
  78
  79        if ( directory < 0 ) {
  80                offset = master->size + directory * master->erasesize;
  81                while (mtd_block_isbad(master, offset)) {
  82                        if (!offset) {
  83                        nogood:
  84                                printk(KERN_NOTICE "Failed to find a non-bad block to check for RedBoot partition table\n");
  85                                return -EIO;
  86                        }
  87                        offset -= master->erasesize;
  88                }
  89        } else {
  90                offset = directory * master->erasesize;
  91                while (mtd_block_isbad(master, offset)) {
  92                        offset += master->erasesize;
  93                        if (offset == master->size)
  94                                goto nogood;
  95                }
  96        }
  97        buf = vmalloc(master->erasesize);
  98
  99        if (!buf)
 100                return -ENOMEM;
 101
 102        printk(KERN_NOTICE "Searching for RedBoot partition table in %s at offset 0x%lx\n",
 103               master->name, offset);
 104
 105        ret = mtd_read(master, offset, master->erasesize, &retlen,
 106                       (void *)buf);
 107
 108        if (ret)
 109                goto out;
 110
 111        if (retlen != master->erasesize) {
 112                ret = -EIO;
 113                goto out;
 114        }
 115
 116        numslots = (master->erasesize / sizeof(struct fis_image_desc));
 117        for (i = 0; i < numslots; i++) {
 118                if (!memcmp(buf[i].name, "FIS directory", 14)) {
 119                        /* This is apparently the FIS directory entry for the
 120                         * FIS directory itself.  The FIS directory size is
 121                         * one erase block; if the buf[i].size field is
 122                         * swab32(erasesize) then we know we are looking at
 123                         * a byte swapped FIS directory - swap all the entries!
 124                         * (NOTE: this is 'size' not 'data_length'; size is
 125                         * the full size of the entry.)
 126                         */
 127
 128                        /* RedBoot can combine the FIS directory and
 129                           config partitions into a single eraseblock;
 130                           we assume wrong-endian if either the swapped
 131                           'size' matches the eraseblock size precisely,
 132                           or if the swapped size actually fits in an
 133                           eraseblock while the unswapped size doesn't. */
 134                        if (swab32(buf[i].size) == master->erasesize ||
 135                            (buf[i].size > master->erasesize
 136                             && swab32(buf[i].size) < master->erasesize)) {
 137                                int j;
 138                                /* Update numslots based on actual FIS directory size */
 139                                numslots = swab32(buf[i].size) / sizeof (struct fis_image_desc);
 140                                for (j = 0; j < numslots; ++j) {
 141
 142                                        /* A single 0xff denotes a deleted entry.
 143                                         * Two of them in a row is the end of the table.
 144                                         */
 145                                        if (buf[j].name[0] == 0xff) {
 146                                                if (buf[j].name[1] == 0xff) {
 147                                                        break;
 148                                                } else {
 149                                                        continue;
 150                                                }
 151                                        }
 152
 153                                        /* The unsigned long fields were written with the
 154                                         * wrong byte sex, name and pad have no byte sex.
 155                                         */
 156                                        swab32s(&buf[j].flash_base);
 157                                        swab32s(&buf[j].mem_base);
 158                                        swab32s(&buf[j].size);
 159                                        swab32s(&buf[j].entry_point);
 160                                        swab32s(&buf[j].data_length);
 161                                        swab32s(&buf[j].desc_cksum);
 162                                        swab32s(&buf[j].file_cksum);
 163                                }
 164                        } else if (buf[i].size < master->erasesize) {
 165                                /* Update numslots based on actual FIS directory size */
 166                                numslots = buf[i].size / sizeof(struct fis_image_desc);
 167                        }
 168                        break;
 169                }
 170        }
 171        if (i == numslots) {
 172                /* Didn't find it */
 173                printk(KERN_NOTICE "No RedBoot partition table detected in %s\n",
 174                       master->name);
 175                ret = 0;
 176                goto out;
 177        }
 178
 179        for (i = 0; i < numslots; i++) {
 180                struct fis_list *new_fl, **prev;
 181
 182                if (buf[i].name[0] == 0xff) {
 183                        if (buf[i].name[1] == 0xff) {
 184                                break;
 185                        } else {
 186                                continue;
 187                        }
 188                }
 189                if (!redboot_checksum(&buf[i]))
 190                        break;
 191
 192                new_fl = kmalloc(sizeof(struct fis_list), GFP_KERNEL);
 193                namelen += strlen(buf[i].name)+1;
 194                if (!new_fl) {
 195                        ret = -ENOMEM;
 196                        goto out;
 197                }
 198                new_fl->img = &buf[i];
 199                if (data && data->origin)
 200                        buf[i].flash_base -= data->origin;
 201                else
 202                        buf[i].flash_base &= master->size-1;
 203
 204                /* I'm sure the JFFS2 code has done me permanent damage.
 205                 * I now think the following is _normal_
 206                 */
 207                prev = &fl;
 208                while(*prev && (*prev)->img->flash_base < new_fl->img->flash_base)
 209                        prev = &(*prev)->next;
 210                new_fl->next = *prev;
 211                *prev = new_fl;
 212
 213                nrparts++;
 214        }
 215#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 216        if (fl->img->flash_base) {
 217                nrparts++;
 218                nulllen = sizeof(nullstring);
 219        }
 220
 221        for (tmp_fl = fl; tmp_fl->next; tmp_fl = tmp_fl->next) {
 222                if (tmp_fl->img->flash_base + tmp_fl->img->size + master->erasesize <= tmp_fl->next->img->flash_base) {
 223                        nrparts++;
 224                        nulllen = sizeof(nullstring);
 225                }
 226        }
 227#endif
 228        parts = kzalloc(sizeof(*parts)*nrparts + nulllen + namelen, GFP_KERNEL);
 229
 230        if (!parts) {
 231                ret = -ENOMEM;
 232                goto out;
 233        }
 234
 235        nullname = (char *)&parts[nrparts];
 236#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 237        if (nulllen > 0) {
 238                strcpy(nullname, nullstring);
 239        }
 240#endif
 241        names = nullname + nulllen;
 242
 243        i=0;
 244
 245#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 246        if (fl->img->flash_base) {
 247               parts[0].name = nullname;
 248               parts[0].size = fl->img->flash_base;
 249               parts[0].offset = 0;
 250                i++;
 251        }
 252#endif
 253        for ( ; i<nrparts; i++) {
 254                parts[i].size = fl->img->size;
 255                parts[i].offset = fl->img->flash_base;
 256                parts[i].name = names;
 257
 258                strcpy(names, fl->img->name);
 259#ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
 260                if (!memcmp(names, "RedBoot", 8) ||
 261                                !memcmp(names, "RedBoot config", 15) ||
 262                                !memcmp(names, "FIS directory", 14)) {
 263                        parts[i].mask_flags = MTD_WRITEABLE;
 264                }
 265#endif
 266                names += strlen(names)+1;
 267
 268#ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
 269                if(fl->next && fl->img->flash_base + fl->img->size + master->erasesize <= fl->next->img->flash_base) {
 270                        i++;
 271                        parts[i].offset = parts[i-1].size + parts[i-1].offset;
 272                        parts[i].size = fl->next->img->flash_base - parts[i].offset;
 273                        parts[i].name = nullname;
 274                }
 275#endif
 276                tmp_fl = fl;
 277                fl = fl->next;
 278                kfree(tmp_fl);
 279        }
 280        ret = nrparts;
 281        *pparts = parts;
 282 out:
 283        while (fl) {
 284                struct fis_list *old = fl;
 285                fl = fl->next;
 286                kfree(old);
 287        }
 288        vfree(buf);
 289        return ret;
 290}
 291
 292static struct mtd_part_parser redboot_parser = {
 293        .owner = THIS_MODULE,
 294        .parse_fn = parse_redboot_partitions,
 295        .name = "RedBoot",
 296};
 297
 298/* mtd parsers will request the module by parser name */
 299MODULE_ALIAS("RedBoot");
 300
 301static int __init redboot_parser_init(void)
 302{
 303        return register_mtd_parser(&redboot_parser);
 304}
 305
 306static void __exit redboot_parser_exit(void)
 307{
 308        deregister_mtd_parser(&redboot_parser);
 309}
 310
 311module_init(redboot_parser_init);
 312module_exit(redboot_parser_exit);
 313
 314MODULE_LICENSE("GPL");
 315MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 316MODULE_DESCRIPTION("Parsing code for RedBoot Flash Image System (FIS) tables");
 317
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