LXR linux/drivers/mtd/parsers/afs.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*======================================================================
   3
   4    drivers/mtd/afs.c: ARM Flash Layout/Partitioning
   5
   6    Copyright © 2000 ARM Limited
   7    Copyright (C) 2019 Linus Walleij
   8
   9
  10   This is access code for flashes using ARM's flash partitioning
  11   standards.
  12
  13======================================================================*/
  14
  15#include <linux/module.h>
  16#include <linux/types.h>
  17#include <linux/kernel.h>
  18#include <linux/slab.h>
  19#include <linux/string.h>
  20#include <linux/init.h>
  21
  22#include <linux/mtd/mtd.h>
  23#include <linux/mtd/map.h>
  24#include <linux/mtd/partitions.h>
  25
  26#define AFSV1_FOOTER_MAGIC 0xA0FFFF9F
  27#define AFSV2_FOOTER_MAGIC1 0x464C5348 /* "FLSH" */
  28#define AFSV2_FOOTER_MAGIC2 0x464F4F54 /* "FOOT" */
  29
  30struct footer_v1 {
  31        u32 image_info_base;    /* Address of first word of ImageFooter  */
  32        u32 image_start;        /* Start of area reserved by this footer */
  33        u32 signature;          /* 'Magic' number proves it's a footer   */
  34        u32 type;               /* Area type: ARM Image, SIB, customer   */
  35        u32 checksum;           /* Just this structure                   */
  36};
  37
  38struct image_info_v1 {
  39        u32 bootFlags;          /* Boot flags, compression etc.          */
  40        u32 imageNumber;        /* Unique number, selects for boot etc.  */
  41        u32 loadAddress;        /* Address program should be loaded to   */
  42        u32 length;             /* Actual size of image                  */
  43        u32 address;            /* Image is executed from here           */
  44        char name[16];          /* Null terminated                       */
  45        u32 headerBase;         /* Flash Address of any stripped header  */
  46        u32 header_length;      /* Length of header in memory            */
  47        u32 headerType;         /* AIF, RLF, s-record etc.               */
  48        u32 checksum;           /* Image checksum (inc. this struct)     */
  49};
  50
  51static u32 word_sum(void *words, int num)
  52{
  53        u32 *p = words;
  54        u32 sum = 0;
  55
  56        while (num--)
  57                sum += *p++;
  58
  59        return sum;
  60}
  61
  62static u32 word_sum_v2(u32 *p, u32 num)
  63{
  64        u32 sum = 0;
  65        int i;
  66
  67        for (i = 0; i < num; i++) {
  68                u32 val;
  69
  70                val = p[i];
  71                if (val > ~sum)
  72                        sum++;
  73                sum += val;
  74        }
  75        return ~sum;
  76}
  77
  78static bool afs_is_v1(struct mtd_info *mtd, u_int off)
  79{
  80        /* The magic is 12 bytes from the end of the erase block */
  81        u_int ptr = off + mtd->erasesize - 12;
  82        u32 magic;
  83        size_t sz;
  84        int ret;
  85
  86        ret = mtd_read(mtd, ptr, 4, &sz, (u_char *)&magic);
  87        if (ret < 0) {
  88                printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
  89                       ptr, ret);
  90                return false;
  91        }
  92        if (ret >= 0 && sz != 4)
  93                return false;
  94
  95        return (magic == AFSV1_FOOTER_MAGIC);
  96}
  97
  98static bool afs_is_v2(struct mtd_info *mtd, u_int off)
  99{
 100        /* The magic is the 8 last bytes of the erase block */
 101        u_int ptr = off + mtd->erasesize - 8;
 102        u32 foot[2];
 103        size_t sz;
 104        int ret;
 105
 106        ret = mtd_read(mtd, ptr, 8, &sz, (u_char *)foot);
 107        if (ret < 0) {
 108                printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
 109                       ptr, ret);
 110                return false;
 111        }
 112        if (ret >= 0 && sz != 8)
 113                return false;
 114
 115        return (foot[0] == AFSV2_FOOTER_MAGIC1 &&
 116                foot[1] == AFSV2_FOOTER_MAGIC2);
 117}
 118
 119static int afs_parse_v1_partition(struct mtd_info *mtd,
 120                                  u_int off, struct mtd_partition *part)
 121{
 122        struct footer_v1 fs;
 123        struct image_info_v1 iis;
 124        u_int mask;
 125        /*
 126         * Static checks cannot see that we bail out if we have an error
 127         * reading the footer.
 128         */
 129        u_int iis_ptr;
 130        u_int img_ptr;
 131        u_int ptr;
 132        size_t sz;
 133        int ret;
 134        int i;
 135
 136        /*
 137         * This is the address mask; we use this to mask off out of
 138         * range address bits.
 139         */
 140        mask = mtd->size - 1;
 141
 142        ptr = off + mtd->erasesize - sizeof(fs);
 143        ret = mtd_read(mtd, ptr, sizeof(fs), &sz, (u_char *)&fs);
 144        if (ret >= 0 && sz != sizeof(fs))
 145                ret = -EINVAL;
 146        if (ret < 0) {
 147                printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
 148                       ptr, ret);
 149                return ret;
 150        }
 151        /*
 152         * Check the checksum.
 153         */
 154        if (word_sum(&fs, sizeof(fs) / sizeof(u32)) != 0xffffffff)
 155                return -EINVAL;
 156
 157        /*
 158         * Hide the SIB (System Information Block)
 159         */
 160        if (fs.type == 2)
 161                return 0;
 162
 163        iis_ptr = fs.image_info_base & mask;
 164        img_ptr = fs.image_start & mask;
 165
 166        /*
 167         * Check the image info base.  This can not
 168         * be located after the footer structure.
 169         */
 170        if (iis_ptr >= ptr)
 171                return 0;
 172
 173        /*
 174         * Check the start of this image.  The image
 175         * data can not be located after this block.
 176         */
 177        if (img_ptr > off)
 178                return 0;
 179
 180        /* Read the image info block */
 181        memset(&iis, 0, sizeof(iis));
 182        ret = mtd_read(mtd, iis_ptr, sizeof(iis), &sz, (u_char *)&iis);
 183        if (ret < 0) {
 184                printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
 185                       iis_ptr, ret);
 186                return -EINVAL;
 187        }
 188
 189        if (sz != sizeof(iis))
 190                return -EINVAL;
 191
 192        /*
 193         * Validate the name - it must be NUL terminated.
 194         */
 195        for (i = 0; i < sizeof(iis.name); i++)
 196                if (iis.name[i] == '\0')
 197                        break;
 198        if (i > sizeof(iis.name))
 199                return -EINVAL;
 200
 201        part->name = kstrdup(iis.name, GFP_KERNEL);
 202        if (!part->name)
 203                return -ENOMEM;
 204
 205        part->size = (iis.length + mtd->erasesize - 1) & ~(mtd->erasesize - 1);
 206        part->offset = img_ptr;
 207        part->mask_flags = 0;
 208
 209        printk("  mtd: at 0x%08x, %5lluKiB, %8u, %s\n",
 210               img_ptr, part->size / 1024,
 211               iis.imageNumber, part->name);
 212
 213        return 0;
 214}
 215
 216static int afs_parse_v2_partition(struct mtd_info *mtd,
 217                                  u_int off, struct mtd_partition *part)
 218{
 219        u_int ptr;
 220        u32 footer[12];
 221        u32 imginfo[36];
 222        char *name;
 223        u32 version;
 224        u32 entrypoint;
 225        u32 attributes;
 226        u32 region_count;
 227        u32 block_start;
 228        u32 block_end;
 229        u32 crc;
 230        size_t sz;
 231        int ret;
 232        int i;
 233        int pad = 0;
 234
 235        pr_debug("Parsing v2 partition @%08x-%08x\n",
 236                 off, off + mtd->erasesize);
 237
 238        /* First read the footer */
 239        ptr = off + mtd->erasesize - sizeof(footer);
 240        ret = mtd_read(mtd, ptr, sizeof(footer), &sz, (u_char *)footer);
 241        if ((ret < 0) || (ret >= 0 && sz != sizeof(footer))) {
 242                pr_err("AFS: mtd read failed at 0x%x: %d\n",
 243                       ptr, ret);
 244                return -EIO;
 245        }
 246        name = (char *) &footer[0];
 247        version = footer[9];
 248        ptr = off + mtd->erasesize - sizeof(footer) - footer[8];
 249
 250        pr_debug("found image \"%s\", version %08x, info @%08x\n",
 251                 name, version, ptr);
 252
 253        /* Then read the image information */
 254        ret = mtd_read(mtd, ptr, sizeof(imginfo), &sz, (u_char *)imginfo);
 255        if ((ret < 0) || (ret >= 0 && sz != sizeof(imginfo))) {
 256                pr_err("AFS: mtd read failed at 0x%x: %d\n",
 257                       ptr, ret);
 258                return -EIO;
 259        }
 260
 261        /* 32bit platforms have 4 bytes padding */
 262        crc = word_sum_v2(&imginfo[1], 34);
 263        if (!crc) {
 264                pr_debug("Padding 1 word (4 bytes)\n");
 265                pad = 1;
 266        } else {
 267                /* 64bit platforms have 8 bytes padding */
 268                crc = word_sum_v2(&imginfo[2], 34);
 269                if (!crc) {
 270                        pr_debug("Padding 2 words (8 bytes)\n");
 271                        pad = 2;
 272                }
 273        }
 274        if (crc) {
 275                pr_err("AFS: bad checksum on v2 image info: %08x\n", crc);
 276                return -EINVAL;
 277        }
 278        entrypoint = imginfo[pad];
 279        attributes = imginfo[pad+1];
 280        region_count = imginfo[pad+2];
 281        block_start = imginfo[20];
 282        block_end = imginfo[21];
 283
 284        pr_debug("image entry=%08x, attr=%08x, regions=%08x, "
 285                 "bs=%08x, be=%08x\n",
 286                 entrypoint, attributes, region_count,
 287                 block_start, block_end);
 288
 289        for (i = 0; i < region_count; i++) {
 290                u32 region_load_addr = imginfo[pad + 3 + i*4];
 291                u32 region_size = imginfo[pad + 4 + i*4];
 292                u32 region_offset = imginfo[pad + 5 + i*4];
 293                u32 region_start;
 294                u32 region_end;
 295
 296                pr_debug("  region %d: address: %08x, size: %08x, "
 297                         "offset: %08x\n",
 298                         i,
 299                         region_load_addr,
 300                         region_size,
 301                         region_offset);
 302
 303                region_start = off + region_offset;
 304                region_end = region_start + region_size;
 305                /* Align partition to end of erase block */
 306                region_end += (mtd->erasesize - 1);
 307                region_end &= ~(mtd->erasesize -1);
 308                pr_debug("   partition start = %08x, partition end = %08x\n",
 309                         region_start, region_end);
 310
 311                /* Create one partition per region */
 312                part->name = kstrdup(name, GFP_KERNEL);
 313                if (!part->name)
 314                        return -ENOMEM;
 315                part->offset = region_start;
 316                part->size = region_end - region_start;
 317                part->mask_flags = 0;
 318        }
 319
 320        return 0;
 321}
 322
 323static int parse_afs_partitions(struct mtd_info *mtd,
 324                                const struct mtd_partition **pparts,
 325                                struct mtd_part_parser_data *data)
 326{
 327        struct mtd_partition *parts;
 328        u_int off, sz;
 329        int ret = 0;
 330        int i;
 331
 332        /* Count the partitions by looping over all erase blocks */
 333        for (i = off = sz = 0; off < mtd->size; off += mtd->erasesize) {
 334                if (afs_is_v1(mtd, off)) {
 335                        sz += sizeof(struct mtd_partition);
 336                        i += 1;
 337                }
 338                if (afs_is_v2(mtd, off)) {
 339                        sz += sizeof(struct mtd_partition);
 340                        i += 1;
 341                }
 342        }
 343
 344        if (!i)
 345                return 0;
 346
 347        parts = kzalloc(sz, GFP_KERNEL);
 348        if (!parts)
 349                return -ENOMEM;
 350
 351        /*
 352         * Identify the partitions
 353         */
 354        for (i = off = 0; off < mtd->size; off += mtd->erasesize) {
 355                if (afs_is_v1(mtd, off)) {
 356                        ret = afs_parse_v1_partition(mtd, off, &parts[i]);
 357                        if (ret)
 358                                goto out_free_parts;
 359                        i++;
 360                }
 361                if (afs_is_v2(mtd, off)) {
 362                        ret = afs_parse_v2_partition(mtd, off, &parts[i]);
 363                        if (ret)
 364                                goto out_free_parts;
 365                        i++;
 366                }
 367        }
 368
 369        *pparts = parts;
 370        return i;
 371
 372out_free_parts:
 373        while (i >= 0) {
 374                kfree(parts[i].name);
 375                i--;
 376        }
 377        kfree(parts);
 378        *pparts = NULL;
 379        return ret;
 380}
 381
 382static const struct of_device_id mtd_parser_afs_of_match_table[] = {
 383        { .compatible = "arm,arm-firmware-suite" },
 384        {},
 385};
 386MODULE_DEVICE_TABLE(of, mtd_parser_afs_of_match_table);
 387
 388static struct mtd_part_parser afs_parser = {
 389        .parse_fn = parse_afs_partitions,
 390        .name = "afs",
 391        .of_match_table = mtd_parser_afs_of_match_table,
 392};
 393module_mtd_part_parser(afs_parser);
 394
 395MODULE_AUTHOR("ARM Ltd");
 396MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
 397MODULE_LICENSE("GPL");
 398