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