block/partitions/acorn.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Copyright (c) 1996-2000 Russell King.
   4  *
   5  *  Scan ADFS partitions on hard disk drives.  Unfortunately, there
   6  *  isn't a standard for partitioning drives on Acorn machines, so
   7  *  every single manufacturer of SCSI and IDE cards created their own
   8  *  method.
   9  */
  10 #include <linux/buffer_head.h>
  11 #include <linux/adfs_fs.h>
  12
  13 #include "check.h"
  14 #include "acorn.h"
  15
  16 /*
  17  * Partition types. (Oh for reusability)
  18  */
  19 #define PARTITION_RISCIX_MFM    1
  20 #define PARTITION_RISCIX_SCSI   2
  21 #define PARTITION_LINUX         9
  22
  23 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
  24         defined(CONFIG_ACORN_PARTITION_ADFS)
  25 static struct adfs_discrecord *
  26 adfs_partition(struct parsed_partitions *state, char *name, char *data,
  27                unsigned long first_sector, int slot)
  28 {
  29         struct adfs_discrecord *dr;
  30         unsigned int nr_sects;
  31
  32         if (adfs_checkbblk(data))
  33                 return NULL;
  34
  35         dr = (struct adfs_discrecord *)(data + 0x1c0);
  36
  37         if (dr->disc_size == 0 && dr->disc_size_high == 0)
  38                 return NULL;
  39
  40         nr_sects = (le32_to_cpu(dr->disc_size_high) << 23) |
  41                    (le32_to_cpu(dr->disc_size) >> 9);
  42
  43         if (name) {
  44                 strlcat(state->pp_buf, " [", PAGE_SIZE);
  45                 strlcat(state->pp_buf, name, PAGE_SIZE);
  46                 strlcat(state->pp_buf, "]", PAGE_SIZE);
  47         }
  48         put_partition(state, slot, first_sector, nr_sects);
  49         return dr;
  50 }
  51 #endif
  52
  53 #ifdef CONFIG_ACORN_PARTITION_RISCIX
  54
  55 struct riscix_part {
  56         __le32  start;
  57         __le32  length;
  58         __le32  one;
  59         char    name[16];
  60 };
  61
  62 struct riscix_record {
  63         __le32  magic;
  64 #define RISCIX_MAGIC    cpu_to_le32(0x4a657320)
  65         __le32  date;
  66         struct riscix_part part[8];
  67 };
  68
  69 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
  70         defined(CONFIG_ACORN_PARTITION_ADFS)
  71 static int riscix_partition(struct parsed_partitions *state,
  72                             unsigned long first_sect, int slot,
  73                             unsigned long nr_sects)
  74 {
  75         Sector sect;
  76         struct riscix_record *rr;
  77
  78         rr = read_part_sector(state, first_sect, &sect);
  79         if (!rr)
  80                 return -1;
  81
  82         strlcat(state->pp_buf, " [RISCiX]", PAGE_SIZE);
  83
  84
  85         if (rr->magic == RISCIX_MAGIC) {
  86                 unsigned long size = nr_sects > 2 ? 2 : nr_sects;
  87                 int part;
  88
  89                 strlcat(state->pp_buf, " <", PAGE_SIZE);
  90
  91                 put_partition(state, slot++, first_sect, size);
  92                 for (part = 0; part < 8; part++) {
  93                         if (rr->part[part].one &&
  94                             memcmp(rr->part[part].name, "All\0", 4)) {
  95                                 put_partition(state, slot++,
  96                                         le32_to_cpu(rr->part[part].start),
  97                                         le32_to_cpu(rr->part[part].length));
  98                                 strlcat(state->pp_buf, "(", PAGE_SIZE);
  99                                 strlcat(state->pp_buf, rr->part[part].name, PAGE_SIZE);
 100                                 strlcat(state->pp_buf, ")", PAGE_SIZE);
 101                         }
 102                 }
 103
 104                 strlcat(state->pp_buf, " >\n", PAGE_SIZE);
 105         } else {
 106                 put_partition(state, slot++, first_sect, nr_sects);
 107         }
 108
 109         put_dev_sector(sect);
 110         return slot;
 111 }
 112 #endif
 113 #endif
 114
 115 #define LINUX_NATIVE_MAGIC 0xdeafa1de
 116 #define LINUX_SWAP_MAGIC   0xdeafab1e
 117
 118 struct linux_part {
 119         __le32 magic;
 120         __le32 start_sect;
 121         __le32 nr_sects;
 122 };
 123
 124 #if defined(CONFIG_ACORN_PARTITION_CUMANA) || \
 125         defined(CONFIG_ACORN_PARTITION_ADFS)
 126 static int linux_partition(struct parsed_partitions *state,
 127                            unsigned long first_sect, int slot,
 128                            unsigned long nr_sects)
 129 {
 130         Sector sect;
 131         struct linux_part *linuxp;
 132         unsigned long size = nr_sects > 2 ? 2 : nr_sects;
 133
 134         strlcat(state->pp_buf, " [Linux]", PAGE_SIZE);
 135
 136         put_partition(state, slot++, first_sect, size);
 137
 138         linuxp = read_part_sector(state, first_sect, &sect);
 139         if (!linuxp)
 140                 return -1;
 141
 142         strlcat(state->pp_buf, " <", PAGE_SIZE);
 143         while (linuxp->magic == cpu_to_le32(LINUX_NATIVE_MAGIC) ||
 144                linuxp->magic == cpu_to_le32(LINUX_SWAP_MAGIC)) {
 145                 if (slot == state->limit)
 146                         break;
 147                 put_partition(state, slot++, first_sect +
 148                                  le32_to_cpu(linuxp->start_sect),
 149                                  le32_to_cpu(linuxp->nr_sects));
 150                 linuxp ++;
 151         }
 152         strlcat(state->pp_buf, " >", PAGE_SIZE);
 153
 154         put_dev_sector(sect);
 155         return slot;
 156 }
 157 #endif
 158
 159 #ifdef CONFIG_ACORN_PARTITION_CUMANA
 160 int adfspart_check_CUMANA(struct parsed_partitions *state)
 161 {
 162         unsigned long first_sector = 0;
 163         unsigned int start_blk = 0;
 164         Sector sect;
 165         unsigned char *data;
 166         char *name = "CUMANA/ADFS";
 167         int first = 1;
 168         int slot = 1;
 169
 170         /*
 171          * Try Cumana style partitions - sector 6 contains ADFS boot block
 172          * with pointer to next 'drive'.
 173          *
 174          * There are unknowns in this code - is the 'cylinder number' of the
 175          * next partition relative to the start of this one - I'm assuming
 176          * it is.
 177          *
 178          * Also, which ID did Cumana use?
 179          *
 180          * This is totally unfinished, and will require more work to get it
 181          * going. Hence it is totally untested.
 182          */
 183         do {
 184                 struct adfs_discrecord *dr;
 185                 unsigned int nr_sects;
 186
 187                 data = read_part_sector(state, start_blk * 2 + 6, &sect);
 188                 if (!data)
 189                         return -1;
 190
 191                 if (slot == state->limit)
 192                         break;
 193
 194                 dr = adfs_partition(state, name, data, first_sector, slot++);
 195                 if (!dr)
 196                         break;
 197
 198                 name = NULL;
 199
 200                 nr_sects = (data[0x1fd] + (data[0x1fe] << 8)) *
 201                            (dr->heads + (dr->lowsector & 0x40 ? 1 : 0)) *
 202                            dr->secspertrack;
 203
 204                 if (!nr_sects)
 205                         break;
 206
 207                 first = 0;
 208                 first_sector += nr_sects;
 209                 start_blk += nr_sects >> (BLOCK_SIZE_BITS - 9);
 210                 nr_sects = 0; /* hmm - should be partition size */
 211
 212                 switch (data[0x1fc] & 15) {
 213                 case 0: /* No partition / ADFS? */
 214                         break;
 215
 216 #ifdef CONFIG_ACORN_PARTITION_RISCIX
 217                 case PARTITION_RISCIX_SCSI:
 218                         /* RISCiX - we don't know how to find the next one. */
 219                         slot = riscix_partition(state, first_sector, slot,
 220                                                 nr_sects);
 221                         break;
 222 #endif
 223
 224                 case PARTITION_LINUX:
 225                         slot = linux_partition(state, first_sector, slot,
 226                                                nr_sects);
 227                         break;
 228                 }
 229                 put_dev_sector(sect);
 230                 if (slot == -1)
 231                         return -1;
 232         } while (1);
 233         put_dev_sector(sect);
 234         return first ? 0 : 1;
 235 }
 236 #endif
 237
 238 #ifdef CONFIG_ACORN_PARTITION_ADFS
 239 /*
 240  * Purpose: allocate ADFS partitions.
 241  *
 242  * Params : hd          - pointer to gendisk structure to store partition info.
 243  *          dev         - device number to access.
 244  *
 245  * Returns: -1 on error, 0 for no ADFS boot sector, 1 for ok.
 246  *
 247  * Alloc  : hda  = whole drive
 248  *          hda1 = ADFS partition on first drive.
 249  *          hda2 = non-ADFS partition.
 250  */
 251 int adfspart_check_ADFS(struct parsed_partitions *state)
 252 {
 253         unsigned long start_sect, nr_sects, sectscyl, heads;
 254         Sector sect;
 255         unsigned char *data;
 256         struct adfs_discrecord *dr;
 257         unsigned char id;
 258         int slot = 1;
 259
 260         data = read_part_sector(state, 6, &sect);
 261         if (!data)
 262                 return -1;
 263
 264         dr = adfs_partition(state, "ADFS", data, 0, slot++);
 265         if (!dr) {
 266                 put_dev_sector(sect);
 267                 return 0;
 268         }
 269
 270         heads = dr->heads + ((dr->lowsector >> 6) & 1);
 271         sectscyl = dr->secspertrack * heads;
 272         start_sect = ((data[0x1fe] << 8) + data[0x1fd]) * sectscyl;
 273         id = data[0x1fc] & 15;
 274         put_dev_sector(sect);
 275
 276         /*
 277          * Work out start of non-adfs partition.
 278          */
 279         nr_sects = (state->bdev->bd_inode->i_size >> 9) - start_sect;
 280
 281         if (start_sect) {
 282                 switch (id) {
 283 #ifdef CONFIG_ACORN_PARTITION_RISCIX
 284                 case PARTITION_RISCIX_SCSI:
 285                 case PARTITION_RISCIX_MFM:
 286                         slot = riscix_partition(state, start_sect, slot,
 287                                                 nr_sects);
 288                         break;
 289 #endif
 290
 291                 case PARTITION_LINUX:
 292                         slot = linux_partition(state, start_sect, slot,
 293                                                nr_sects);
 294                         break;
 295                 }
 296         }
 297         strlcat(state->pp_buf, "\n", PAGE_SIZE);
 298         return 1;
 299 }
 300 #endif
 301
 302 #ifdef CONFIG_ACORN_PARTITION_ICS
 303
 304 struct ics_part {
 305         __le32 start;
 306         __le32 size;
 307 };
 308
 309 static int adfspart_check_ICSLinux(struct parsed_partitions *state,
 310                                    unsigned long block)
 311 {
 312         Sector sect;
 313         unsigned char *data = read_part_sector(state, block, &sect);
 314         int result = 0;
 315
 316         if (data) {
 317                 if (memcmp(data, "LinuxPart", 9) == 0)
 318                         result = 1;
 319                 put_dev_sector(sect);
 320         }
 321
 322         return result;
 323 }
 324
 325 /*
 326  * Check for a valid ICS partition using the checksum.
 327  */
 328 static inline int valid_ics_sector(const unsigned char *data)
 329 {
 330         unsigned long sum;
 331         int i;
 332
 333         for (i = 0, sum = 0x50617274; i < 508; i++)
 334                 sum += data[i];
 335
 336         sum -= le32_to_cpu(*(__le32 *)(&data[508]));
 337
 338         return sum == 0;
 339 }
 340
 341 /*
 342  * Purpose: allocate ICS partitions.
 343  * Params : hd          - pointer to gendisk structure to store partition info.
 344  *          dev         - device number to access.
 345  * Returns: -1 on error, 0 for no ICS table, 1 for partitions ok.
 346  * Alloc  : hda  = whole drive
 347  *          hda1 = ADFS partition 0 on first drive.
 348  *          hda2 = ADFS partition 1 on first drive.
 349  *              ..etc..
 350  */
 351 int adfspart_check_ICS(struct parsed_partitions *state)
 352 {
 353         const unsigned char *data;
 354         const struct ics_part *p;
 355         int slot;
 356         Sector sect;
 357
 358         /*
 359          * Try ICS style partitions - sector 0 contains partition info.
 360          */
 361         data = read_part_sector(state, 0, &sect);
 362         if (!data)
 363                 return -1;
 364
 365         if (!valid_ics_sector(data)) {
 366                 put_dev_sector(sect);
 367                 return 0;
 368         }
 369
 370         strlcat(state->pp_buf, " [ICS]", PAGE_SIZE);
 371
 372         for (slot = 1, p = (const struct ics_part *)data; p->size; p++) {
 373                 u32 start = le32_to_cpu(p->start);
 374                 s32 size = le32_to_cpu(p->size); /* yes, it's signed. */
 375
 376                 if (slot == state->limit)
 377                         break;
 378
 379                 /*
 380                  * Negative sizes tell the RISC OS ICS driver to ignore
 381                  * this partition - in effect it says that this does not
 382                  * contain an ADFS filesystem.
 383                  */
 384                 if (size < 0) {
 385                         size = -size;
 386
 387                         /*
 388                          * Our own extension - We use the first sector
 389                          * of the partition to identify what type this
 390                          * partition is.  We must not make this visible
 391                          * to the filesystem.
 392                          */
 393                         if (size > 1 && adfspart_check_ICSLinux(state, start)) {
 394                                 start += 1;
 395                                 size -= 1;
 396                         }
 397                 }
 398
 399                 if (size)
 400                         put_partition(state, slot++, start, size);
 401         }
 402
 403         put_dev_sector(sect);
 404         strlcat(state->pp_buf, "\n", PAGE_SIZE);
 405         return 1;
 406 }
 407 #endif
 408
 409 #ifdef CONFIG_ACORN_PARTITION_POWERTEC
 410 struct ptec_part {
 411         __le32 unused1;
 412         __le32 unused2;
 413         __le32 start;
 414         __le32 size;
 415         __le32 unused5;
 416         char type[8];
 417 };
 418
 419 static inline int valid_ptec_sector(const unsigned char *data)
 420 {
 421         unsigned char checksum = 0x2a;
 422         int i;
 423
 424         /*
 425          * If it looks like a PC/BIOS partition, then it
 426          * probably isn't PowerTec.
 427          */
 428         if (data[510] == 0x55 && data[511] == 0xaa)
 429                 return 0;
 430
 431         for (i = 0; i < 511; i++)
 432                 checksum += data[i];
 433
 434         return checksum == data[511];
 435 }
 436
 437 /*
 438  * Purpose: allocate ICS partitions.
 439  * Params : hd          - pointer to gendisk structure to store partition info.
 440  *          dev         - device number to access.
 441  * Returns: -1 on error, 0 for no ICS table, 1 for partitions ok.
 442  * Alloc  : hda  = whole drive
 443  *          hda1 = ADFS partition 0 on first drive.
 444  *          hda2 = ADFS partition 1 on first drive.
 445  *              ..etc..
 446  */
 447 int adfspart_check_POWERTEC(struct parsed_partitions *state)
 448 {
 449         Sector sect;
 450         const unsigned char *data;
 451         const struct ptec_part *p;
 452         int slot = 1;
 453         int i;
 454
 455         data = read_part_sector(state, 0, &sect);
 456         if (!data)
 457                 return -1;
 458
 459         if (!valid_ptec_sector(data)) {
 460                 put_dev_sector(sect);
 461                 return 0;
 462         }
 463
 464         strlcat(state->pp_buf, " [POWERTEC]", PAGE_SIZE);
 465
 466         for (i = 0, p = (const struct ptec_part *)data; i < 12; i++, p++) {
 467                 u32 start = le32_to_cpu(p->start);
 468                 u32 size = le32_to_cpu(p->size);
 469
 470                 if (size)
 471                         put_partition(state, slot++, start, size);
 472         }
 473
 474         put_dev_sector(sect);
 475         strlcat(state->pp_buf, "\n", PAGE_SIZE);
 476         return 1;
 477 }
 478 #endif
 479
 480 #ifdef CONFIG_ACORN_PARTITION_EESOX
 481 struct eesox_part {
 482         char    magic[6];
 483         char    name[10];
 484         __le32  start;
 485         __le32  unused6;
 486         __le32  unused7;
 487         __le32  unused8;
 488 };
 489
 490 /*
 491  * Guess who created this format?
 492  */
 493 static const char eesox_name[] = {
 494         'N', 'e', 'i', 'l', ' ',
 495         'C', 'r', 'i', 't', 'c', 'h', 'e', 'l', 'l', ' ', ' '
 496 };
 497
 498 /*
 499  * EESOX SCSI partition format.
 500  *
 501  * This is a goddamned awful partition format.  We don't seem to store
 502  * the size of the partition in this table, only the start addresses.
 503  *
 504  * There are two possibilities where the size comes from:
 505  *  1. The individual ADFS boot block entries that are placed on the disk.
 506  *  2. The start address of the next entry.
 507  */
 508 int adfspart_check_EESOX(struct parsed_partitions *state)
 509 {
 510         Sector sect;
 511         const unsigned char *data;
 512         unsigned char buffer[256];
 513         struct eesox_part *p;
 514         sector_t start = 0;
 515         int i, slot = 1;
 516
 517         data = read_part_sector(state, 7, &sect);
 518         if (!data)
 519                 return -1;
 520
 521         /*
 522          * "Decrypt" the partition table.  God knows why...
 523          */
 524         for (i = 0; i < 256; i++)
 525                 buffer[i] = data[i] ^ eesox_name[i & 15];
 526
 527         put_dev_sector(sect);
 528
 529         for (i = 0, p = (struct eesox_part *)buffer; i < 8; i++, p++) {
 530                 sector_t next;
 531
 532                 if (memcmp(p->magic, "Eesox", 6))
 533                         break;
 534
 535                 next = le32_to_cpu(p->start);
 536                 if (i)
 537                         put_partition(state, slot++, start, next - start);
 538                 start = next;
 539         }
 540
 541         if (i != 0) {
 542                 sector_t size;
 543
 544                 size = get_capacity(state->bdev->bd_disk);
 545                 put_partition(state, slot++, start, size - start);
 546                 strlcat(state->pp_buf, "\n", PAGE_SIZE);
 547         }
 548
 549         return i ? 1 : 0;
 550 }
 551 #endif