drivers/mtd/ssfdc.c

   1 /*
   2  * Linux driver for SSFDC Flash Translation Layer (Read only)
   3  * (c) 2005 Eptar srl
   4  * Author: Claudio Lanconelli <lanconelli.claudio@eptar.com>
   5  *
   6  * Based on NTFL and MTDBLOCK_RO drivers
   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 version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/slab.h>
  17 #include <linux/hdreg.h>
  18 #include <linux/mtd/mtd.h>
  19 #include <linux/mtd/nand.h>
  20 #include <linux/mtd/blktrans.h>
  21
  22 struct ssfdcr_record {
  23         struct mtd_blktrans_dev mbd;
  24         int usecount;
  25         unsigned char heads;
  26         unsigned char sectors;
  27         unsigned short cylinders;
  28         int cis_block;                  /* block n. containing CIS/IDI */
  29         int erase_size;                 /* phys_block_size */
  30         unsigned short *logic_block_map; /* all zones (max 8192 phys blocks on
  31                                             the 128MiB) */
  32         int map_len;                    /* n. phys_blocks on the card */
  33 };
  34
  35 #define SSFDCR_MAJOR            257
  36 #define SSFDCR_PARTN_BITS       3
  37
  38 #define SECTOR_SIZE             512
  39 #define SECTOR_SHIFT            9
  40 #define OOB_SIZE                16
  41
  42 #define MAX_LOGIC_BLK_PER_ZONE  1000
  43 #define MAX_PHYS_BLK_PER_ZONE   1024
  44
  45 #define KiB(x)  ( (x) * 1024L )
  46 #define MiB(x)  ( KiB(x) * 1024L )
  47
  48 /** CHS Table
  49                 1MiB    2MiB    4MiB    8MiB    16MiB   32MiB   64MiB   128MiB
  50 NCylinder       125     125     250     250     500     500     500     500
  51 NHead           4       4       4       4       4       8       8       16
  52 NSector         4       8       8       16      16      16      32      32
  53 SumSector       2,000   4,000   8,000   16,000  32,000  64,000  128,000 256,000
  54 SectorSize      512     512     512     512     512     512     512     512
  55 **/
  56
  57 typedef struct {
  58         unsigned long size;
  59         unsigned short cyl;
  60         unsigned char head;
  61         unsigned char sec;
  62 } chs_entry_t;
  63
  64 /* Must be ordered by size */
  65 static const chs_entry_t chs_table[] = {
  66         { MiB(  1), 125,  4,  4 },
  67         { MiB(  2), 125,  4,  8 },
  68         { MiB(  4), 250,  4,  8 },
  69         { MiB(  8), 250,  4, 16 },
  70         { MiB( 16), 500,  4, 16 },
  71         { MiB( 32), 500,  8, 16 },
  72         { MiB( 64), 500,  8, 32 },
  73         { MiB(128), 500, 16, 32 },
  74         { 0 },
  75 };
  76
  77 static int get_chs(unsigned long size, unsigned short *cyl, unsigned char *head,
  78                         unsigned char *sec)
  79 {
  80         int k;
  81         int found = 0;
  82
  83         k = 0;
  84         while (chs_table[k].size > 0 && size > chs_table[k].size)
  85                 k++;
  86
  87         if (chs_table[k].size > 0) {
  88                 if (cyl)
  89                         *cyl = chs_table[k].cyl;
  90                 if (head)
  91                         *head = chs_table[k].head;
  92                 if (sec)
  93                         *sec = chs_table[k].sec;
  94                 found = 1;
  95         }
  96
  97         return found;
  98 }
  99
 100 /* These bytes are the signature for the CIS/IDI sector */
 101 static const uint8_t cis_numbers[] = {
 102         0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
 103 };
 104
 105 /* Read and check for a valid CIS sector */
 106 static int get_valid_cis_sector(struct mtd_info *mtd)
 107 {
 108         int ret, k, cis_sector;
 109         size_t retlen;
 110         loff_t offset;
 111         uint8_t *sect_buf;
 112
 113         cis_sector = -1;
 114
 115         sect_buf = kmalloc(SECTOR_SIZE, GFP_KERNEL);
 116         if (!sect_buf)
 117                 goto out;
 118
 119         /*
 120          * Look for CIS/IDI sector on the first GOOD block (give up after 4 bad
 121          * blocks). If the first good block doesn't contain CIS number the flash
 122          * is not SSFDC formatted
 123          */
 124         for (k = 0, offset = 0; k < 4; k++, offset += mtd->erasesize) {
 125                 if (!mtd->block_isbad(mtd, offset)) {
 126                         ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen,
 127                                 sect_buf);
 128
 129                         /* CIS pattern match on the sector buffer */
 130                         if (ret < 0 || retlen != SECTOR_SIZE) {
 131                                 printk(KERN_WARNING
 132                                         "SSFDC_RO:can't read CIS/IDI sector\n");
 133                         } else if (!memcmp(sect_buf, cis_numbers,
 134                                         sizeof(cis_numbers))) {
 135                                 /* Found */
 136                                 cis_sector = (int)(offset >> SECTOR_SHIFT);
 137                         } else {
 138                                 DEBUG(MTD_DEBUG_LEVEL1,
 139                                         "SSFDC_RO: CIS/IDI sector not found"
 140                                         " on %s (mtd%d)\n", mtd->name,
 141                                         mtd->index);
 142                         }
 143                         break;
 144                 }
 145         }
 146
 147         kfree(sect_buf);
 148  out:
 149         return cis_sector;
 150 }
 151
 152 /* Read physical sector (wrapper to MTD_READ) */
 153 static int read_physical_sector(struct mtd_info *mtd, uint8_t *sect_buf,
 154                                 int sect_no)
 155 {
 156         int ret;
 157         size_t retlen;
 158         loff_t offset = (loff_t)sect_no << SECTOR_SHIFT;
 159
 160         ret = mtd->read(mtd, offset, SECTOR_SIZE, &retlen, sect_buf);
 161         if (ret < 0 || retlen != SECTOR_SIZE)
 162                 return -1;
 163
 164         return 0;
 165 }
 166
 167 /* Read redundancy area (wrapper to MTD_READ_OOB */
 168 static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf)
 169 {
 170         struct mtd_oob_ops ops;
 171         int ret;
 172
 173         ops.mode = MTD_OOB_RAW;
 174         ops.ooboffs = 0;
 175         ops.ooblen = mtd->oobsize;
 176         ops.len = OOB_SIZE;
 177         ops.oobbuf = buf;
 178         ops.datbuf = NULL;
 179
 180         ret = mtd->read_oob(mtd, offs, &ops);
 181         if (ret < 0 || ops.retlen != OOB_SIZE)
 182                 return -1;
 183
 184         return 0;
 185 }
 186
 187 /* Parity calculator on a word of n bit size */
 188 static int get_parity(int number, int size)
 189 {
 190         int k;
 191         int parity;
 192
 193         parity = 1;
 194         for (k = 0; k < size; k++) {
 195                 parity += (number >> k);
 196                 parity &= 1;
 197         }
 198         return parity;
 199 }
 200
 201 /* Read and validate the logical block address field stored in the OOB */
 202 static int get_logical_address(uint8_t *oob_buf)
 203 {
 204         int block_address, parity;
 205         int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */
 206         int j;
 207         int ok = 0;
 208
 209         /*
 210          * Look for the first valid logical address
 211          * Valid address has fixed pattern on most significant bits and
 212          * parity check
 213          */
 214         for (j = 0; j < ARRAY_SIZE(offset); j++) {
 215                 block_address = ((int)oob_buf[offset[j]] << 8) |
 216                         oob_buf[offset[j]+1];
 217
 218                 /* Check for the signature bits in the address field (MSBits) */
 219                 if ((block_address & ~0x7FF) == 0x1000) {
 220                         parity = block_address & 0x01;
 221                         block_address &= 0x7FF;
 222                         block_address >>= 1;
 223
 224                         if (get_parity(block_address, 10) != parity) {
 225                                 DEBUG(MTD_DEBUG_LEVEL0,
 226                                         "SSFDC_RO: logical address field%d"
 227                                         "parity error(0x%04X)\n", j+1,
 228                                         block_address);
 229                         } else {
 230                                 ok = 1;
 231                                 break;
 232                         }
 233                 }
 234         }
 235
 236         if (!ok)
 237                 block_address = -2;
 238
 239         DEBUG(MTD_DEBUG_LEVEL3, "SSFDC_RO: get_logical_address() %d\n",
 240                 block_address);
 241
 242         return block_address;
 243 }
 244
 245 /* Build the logic block map */
 246 static int build_logical_block_map(struct ssfdcr_record *ssfdc)
 247 {
 248         unsigned long offset;
 249         uint8_t oob_buf[OOB_SIZE];
 250         int ret, block_address, phys_block;
 251         struct mtd_info *mtd = ssfdc->mbd.mtd;
 252
 253         DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: build_block_map() nblks=%d (%luK)\n",
 254               ssfdc->map_len,
 255               (unsigned long)ssfdc->map_len * ssfdc->erase_size / 1024);
 256
 257         /* Scan every physical block, skip CIS block */
 258         for (phys_block = ssfdc->cis_block + 1; phys_block < ssfdc->map_len;
 259                         phys_block++) {
 260                 offset = (unsigned long)phys_block * ssfdc->erase_size;
 261                 if (mtd->block_isbad(mtd, offset))
 262                         continue;       /* skip bad blocks */
 263
 264                 ret = read_raw_oob(mtd, offset, oob_buf);
 265                 if (ret < 0) {
 266                         DEBUG(MTD_DEBUG_LEVEL0,
 267                                 "SSFDC_RO: mtd read_oob() failed at %lu\n",
 268                                 offset);
 269                         return -1;
 270                 }
 271                 block_address = get_logical_address(oob_buf);
 272
 273                 /* Skip invalid addresses */
 274                 if (block_address >= 0 &&
 275                                 block_address < MAX_LOGIC_BLK_PER_ZONE) {
 276                         int zone_index;
 277
 278                         zone_index = phys_block / MAX_PHYS_BLK_PER_ZONE;
 279                         block_address += zone_index * MAX_LOGIC_BLK_PER_ZONE;
 280                         ssfdc->logic_block_map[block_address] =
 281                                 (unsigned short)phys_block;
 282
 283                         DEBUG(MTD_DEBUG_LEVEL2,
 284                                 "SSFDC_RO: build_block_map() phys_block=%d,"
 285                                 "logic_block_addr=%d, zone=%d\n",
 286                                 phys_block, block_address, zone_index);
 287                 }
 288         }
 289         return 0;
 290 }
 291
 292 static void ssfdcr_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
 293 {
 294         struct ssfdcr_record *ssfdc;
 295         int cis_sector;
 296
 297         /* Check for small page NAND flash */
 298         if (mtd->type != MTD_NANDFLASH || mtd->oobsize != OOB_SIZE)
 299                 return;
 300
 301         /* Check for SSDFC format by reading CIS/IDI sector */
 302         cis_sector = get_valid_cis_sector(mtd);
 303         if (cis_sector == -1)
 304                 return;
 305
 306         ssfdc = kzalloc(sizeof(struct ssfdcr_record), GFP_KERNEL);
 307         if (!ssfdc) {
 308                 printk(KERN_WARNING
 309                         "SSFDC_RO: out of memory for data structures\n");
 310                 return;
 311         }
 312
 313         ssfdc->mbd.mtd = mtd;
 314         ssfdc->mbd.devnum = -1;
 315         ssfdc->mbd.blksize = SECTOR_SIZE;
 316         ssfdc->mbd.tr = tr;
 317         ssfdc->mbd.readonly = 1;
 318
 319         ssfdc->cis_block = cis_sector / (mtd->erasesize >> SECTOR_SHIFT);
 320         ssfdc->erase_size = mtd->erasesize;
 321         ssfdc->map_len = mtd->size / mtd->erasesize;
 322
 323         DEBUG(MTD_DEBUG_LEVEL1,
 324                 "SSFDC_RO: cis_block=%d,erase_size=%d,map_len=%d,n_zones=%d\n",
 325                 ssfdc->cis_block, ssfdc->erase_size, ssfdc->map_len,
 326                 (ssfdc->map_len + MAX_PHYS_BLK_PER_ZONE - 1) /
 327                 MAX_PHYS_BLK_PER_ZONE);
 328
 329         /* Set geometry */
 330         ssfdc->heads = 16;
 331         ssfdc->sectors = 32;
 332         get_chs(mtd->size, NULL, &ssfdc->heads, &ssfdc->sectors);
 333         ssfdc->cylinders = (unsigned short)((mtd->size >> SECTOR_SHIFT) /
 334                         ((long)ssfdc->sectors * (long)ssfdc->heads));
 335
 336         DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: using C:%d H:%d S:%d == %ld sects\n",
 337                 ssfdc->cylinders, ssfdc->heads , ssfdc->sectors,
 338                 (long)ssfdc->cylinders * (long)ssfdc->heads *
 339                 (long)ssfdc->sectors);
 340
 341         ssfdc->mbd.size = (long)ssfdc->heads * (long)ssfdc->cylinders *
 342                                 (long)ssfdc->sectors;
 343
 344         /* Allocate logical block map */
 345         ssfdc->logic_block_map = kmalloc(sizeof(ssfdc->logic_block_map[0]) *
 346                                          ssfdc->map_len, GFP_KERNEL);
 347         if (!ssfdc->logic_block_map) {
 348                 printk(KERN_WARNING
 349                         "SSFDC_RO: out of memory for data structures\n");
 350                 goto out_err;
 351         }
 352         memset(ssfdc->logic_block_map, 0xff, sizeof(ssfdc->logic_block_map[0]) *
 353                 ssfdc->map_len);
 354
 355         /* Build logical block map */
 356         if (build_logical_block_map(ssfdc) < 0)
 357                 goto out_err;
 358
 359         /* Register device + partitions */
 360         if (add_mtd_blktrans_dev(&ssfdc->mbd))
 361                 goto out_err;
 362
 363         printk(KERN_INFO "SSFDC_RO: Found ssfdc%c on mtd%d (%s)\n",
 364                 ssfdc->mbd.devnum + 'a', mtd->index, mtd->name);
 365         return;
 366
 367 out_err:
 368         kfree(ssfdc->logic_block_map);
 369         kfree(ssfdc);
 370 }
 371
 372 static void ssfdcr_remove_dev(struct mtd_blktrans_dev *dev)
 373 {
 374         struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
 375
 376         DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: remove_dev (i=%d)\n", dev->devnum);
 377
 378         del_mtd_blktrans_dev(dev);
 379         kfree(ssfdc->logic_block_map);
 380         kfree(ssfdc);
 381 }
 382
 383 static int ssfdcr_readsect(struct mtd_blktrans_dev *dev,
 384                                 unsigned long logic_sect_no, char *buf)
 385 {
 386         struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
 387         int sectors_per_block, offset, block_address;
 388
 389         sectors_per_block = ssfdc->erase_size >> SECTOR_SHIFT;
 390         offset = (int)(logic_sect_no % sectors_per_block);
 391         block_address = (int)(logic_sect_no / sectors_per_block);
 392
 393         DEBUG(MTD_DEBUG_LEVEL3,
 394                 "SSFDC_RO: ssfdcr_readsect(%lu) sec_per_blk=%d, ofst=%d,"
 395                 " block_addr=%d\n", logic_sect_no, sectors_per_block, offset,
 396                 block_address);
 397
 398         if (block_address >= ssfdc->map_len)
 399                 BUG();
 400
 401         block_address = ssfdc->logic_block_map[block_address];
 402
 403         DEBUG(MTD_DEBUG_LEVEL3,
 404                 "SSFDC_RO: ssfdcr_readsect() phys_block_addr=%d\n",
 405                 block_address);
 406
 407         if (block_address < 0xffff) {
 408                 unsigned long sect_no;
 409
 410                 sect_no = (unsigned long)block_address * sectors_per_block +
 411                                 offset;
 412
 413                 DEBUG(MTD_DEBUG_LEVEL3,
 414                         "SSFDC_RO: ssfdcr_readsect() phys_sect_no=%lu\n",
 415                         sect_no);
 416
 417                 if (read_physical_sector(ssfdc->mbd.mtd, buf, sect_no) < 0)
 418                         return -EIO;
 419         } else {
 420                 memset(buf, 0xff, SECTOR_SIZE);
 421         }
 422
 423         return 0;
 424 }
 425
 426 static int ssfdcr_getgeo(struct mtd_blktrans_dev *dev,  struct hd_geometry *geo)
 427 {
 428         struct ssfdcr_record *ssfdc = (struct ssfdcr_record *)dev;
 429
 430         DEBUG(MTD_DEBUG_LEVEL1, "SSFDC_RO: ssfdcr_getgeo() C=%d, H=%d, S=%d\n",
 431                         ssfdc->cylinders, ssfdc->heads, ssfdc->sectors);
 432
 433         geo->heads = ssfdc->heads;
 434         geo->sectors = ssfdc->sectors;
 435         geo->cylinders = ssfdc->cylinders;
 436
 437         return 0;
 438 }
 439
 440 /****************************************************************************
 441  *
 442  * Module stuff
 443  *
 444  ****************************************************************************/
 445
 446 static struct mtd_blktrans_ops ssfdcr_tr = {
 447         .name           = "ssfdc",
 448         .major          = SSFDCR_MAJOR,
 449         .part_bits      = SSFDCR_PARTN_BITS,
 450         .getgeo         = ssfdcr_getgeo,
 451         .readsect       = ssfdcr_readsect,
 452         .add_mtd        = ssfdcr_add_mtd,
 453         .remove_dev     = ssfdcr_remove_dev,
 454         .owner          = THIS_MODULE,
 455 };
 456
 457 static int __init init_ssfdcr(void)
 458 {
 459         printk(KERN_INFO "SSFDC read-only Flash Translation layer\n");
 460
 461         return register_mtd_blktrans(&ssfdcr_tr);
 462 }
 463
 464 static void __exit cleanup_ssfdcr(void)
 465 {
 466         deregister_mtd_blktrans(&ssfdcr_tr);
 467 }
 468
 469 module_init(init_ssfdcr);
 470 module_exit(cleanup_ssfdcr);
 471
 472 MODULE_LICENSE("GPL");
 473 MODULE_AUTHOR("Claudio Lanconelli <lanconelli.claudio@eptar.com>");
 474 MODULE_DESCRIPTION("Flash Translation Layer for read-only SSFDC SmartMedia card");