yaffs_tagscompat.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2010 Aleph One Ltd.
   5  *   for Toby Churchill Ltd and Brightstar Engineering
   6  *
   7  * Created by Charles Manning <charles@aleph1.co.uk>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include "yaffs_guts.h"
  15 #include "yaffs_tagscompat.h"
  16 #include "yaffs_ecc.h"
  17 #include "yaffs_getblockinfo.h"
  18 #include "yaffs_trace.h"
  19
  20 static void yaffs_handle_rd_data_error(yaffs_dev_t *dev, int nand_chunk);
  21 #ifdef NOTYET
  22 static void yaffs_check_written_block(yaffs_dev_t *dev, int nand_chunk);
  23 static void yaffs_handle_chunk_wr_ok(yaffs_dev_t *dev, int nand_chunk,
  24                                      const __u8 *data,
  25                                      const yaffs_spare *spare);
  26 static void yaffs_handle_chunk_update(yaffs_dev_t *dev, int nand_chunk,
  27                                     const yaffs_spare *spare);
  28 static void yaffs_handle_chunk_wr_error(yaffs_dev_t *dev, int nand_chunk);
  29 #endif
  30
  31 static const char yaffs_count_bits_table[256] = {
  32         0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
  33         1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
  34         1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
  35         2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
  36         1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
  37         2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
  38         2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
  39         3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
  40         1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
  41         2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
  42         2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
  43         3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
  44         2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
  45         3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
  46         3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
  47         4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
  48 };
  49
  50 int yaffs_count_bits(__u8 x)
  51 {
  52         int ret_val;
  53         ret_val = yaffs_count_bits_table[x];
  54         return ret_val;
  55 }
  56
  57 /********** Tags ECC calculations  *********/
  58
  59 void yaffs_calc_ecc(const __u8 *data, yaffs_spare *spare)
  60 {
  61         yaffs_ecc_cacl(data, spare->ecc1);
  62         yaffs_ecc_cacl(&data[256], spare->ecc2);
  63 }
  64
  65 void yaffs_calc_tags_ecc(yaffs_tags_t *tags)
  66 {
  67         /* Calculate an ecc */
  68
  69         unsigned char *b = ((yaffs_tags_union_t *) tags)->as_bytes;
  70         unsigned i, j;
  71         unsigned ecc = 0;
  72         unsigned bit = 0;
  73
  74         tags->ecc = 0;
  75
  76         for (i = 0; i < 8; i++) {
  77                 for (j = 1; j & 0xff; j <<= 1) {
  78                         bit++;
  79                         if (b[i] & j)
  80                                 ecc ^= bit;
  81                 }
  82         }
  83
  84         tags->ecc = ecc;
  85
  86 }
  87
  88 int yaffs_check_tags_ecc(yaffs_tags_t *tags)
  89 {
  90         unsigned ecc = tags->ecc;
  91
  92         yaffs_calc_tags_ecc(tags);
  93
  94         ecc ^= tags->ecc;
  95
  96         if (ecc && ecc <= 64) {
  97                 /* TODO: Handle the failure better. Retire? */
  98                 unsigned char *b = ((yaffs_tags_union_t *) tags)->as_bytes;
  99
 100                 ecc--;
 101
 102                 b[ecc / 8] ^= (1 << (ecc & 7));
 103
 104                 /* Now recvalc the ecc */
 105                 yaffs_calc_tags_ecc(tags);
 106
 107                 return 1;       /* recovered error */
 108         } else if (ecc) {
 109                 /* Wierd ecc failure value */
 110                 /* TODO Need to do somethiong here */
 111                 return -1;      /* unrecovered error */
 112         }
 113
 114         return 0;
 115 }
 116
 117 /********** Tags **********/
 118
 119 static void yaffs_load_tags_to_spare(yaffs_spare *spare_ptr,
 120                                 yaffs_tags_t *tags_ptr)
 121 {
 122         yaffs_tags_union_t *tu = (yaffs_tags_union_t *) tags_ptr;
 123
 124         yaffs_calc_tags_ecc(tags_ptr);
 125
 126         spare_ptr->tb0 = tu->as_bytes[0];
 127         spare_ptr->tb1 = tu->as_bytes[1];
 128         spare_ptr->tb2 = tu->as_bytes[2];
 129         spare_ptr->tb3 = tu->as_bytes[3];
 130         spare_ptr->tb4 = tu->as_bytes[4];
 131         spare_ptr->tb5 = tu->as_bytes[5];
 132         spare_ptr->tb6 = tu->as_bytes[6];
 133         spare_ptr->tb7 = tu->as_bytes[7];
 134 }
 135
 136 static void yaffs_get_tags_from_spare(yaffs_dev_t *dev, yaffs_spare *spare_ptr,
 137                                 yaffs_tags_t *tags_ptr)
 138 {
 139         yaffs_tags_union_t *tu = (yaffs_tags_union_t *) tags_ptr;
 140         int result;
 141
 142         tu->as_bytes[0] = spare_ptr->tb0;
 143         tu->as_bytes[1] = spare_ptr->tb1;
 144         tu->as_bytes[2] = spare_ptr->tb2;
 145         tu->as_bytes[3] = spare_ptr->tb3;
 146         tu->as_bytes[4] = spare_ptr->tb4;
 147         tu->as_bytes[5] = spare_ptr->tb5;
 148         tu->as_bytes[6] = spare_ptr->tb6;
 149         tu->as_bytes[7] = spare_ptr->tb7;
 150
 151         result = yaffs_check_tags_ecc(tags_ptr);
 152         if (result > 0)
 153                 dev->n_tags_ecc_fixed++;
 154         else if (result < 0)
 155                 dev->n_tags_ecc_unfixed++;
 156 }
 157
 158 static void yaffs_spare_init(yaffs_spare *spare)
 159 {
 160         memset(spare, 0xFF, sizeof(yaffs_spare));
 161 }
 162
 163 static int yaffs_wr_nand(struct yaffs_dev_s *dev,
 164                                 int nand_chunk, const __u8 *data,
 165                                 yaffs_spare *spare)
 166 {
 167         if (nand_chunk < dev->param.start_block * dev->param.chunks_per_block) {
 168                 T(YAFFS_TRACE_ERROR,
 169                   (TSTR("**>> yaffs chunk %d is not valid" TENDSTR),
 170                    nand_chunk));
 171                 return YAFFS_FAIL;
 172         }
 173
 174         return dev->param.write_chunk_fn(dev, nand_chunk, data, spare);
 175 }
 176
 177 static int yaffs_rd_chunk_nand(struct yaffs_dev_s *dev,
 178                                    int nand_chunk,
 179                                    __u8 *data,
 180                                    yaffs_spare *spare,
 181                                    yaffs_ecc_result *ecc_result,
 182                                    int correct_errors)
 183 {
 184         int ret_val;
 185         yaffs_spare local_spare;
 186
 187         if (!spare && data) {
 188                 /* If we don't have a real spare, then we use a local one. */
 189                 /* Need this for the calculation of the ecc */
 190                 spare = &local_spare;
 191         }
 192
 193         if (!dev->param.use_nand_ecc) {
 194                 ret_val = dev->param.read_chunk_fn(dev, nand_chunk, data, spare);
 195                 if (data && correct_errors) {
 196                         /* Do ECC correction */
 197                         /* Todo handle any errors */
 198                         int ecc_result1, ecc_result2;
 199                         __u8 calc_ecc[3];
 200
 201                         yaffs_ecc_cacl(data, calc_ecc);
 202                         ecc_result1 =
 203                             yaffs_ecc_correct(data, spare->ecc1, calc_ecc);
 204                         yaffs_ecc_cacl(&data[256], calc_ecc);
 205                         ecc_result2 =
 206                             yaffs_ecc_correct(&data[256], spare->ecc2, calc_ecc);
 207
 208                         if (ecc_result1 > 0) {
 209                                 T(YAFFS_TRACE_ERROR,
 210                                   (TSTR
 211                                    ("**>>yaffs ecc error fix performed on chunk %d:0"
 212                                     TENDSTR), nand_chunk));
 213                                 dev->n_ecc_fixed++;
 214                         } else if (ecc_result1 < 0) {
 215                                 T(YAFFS_TRACE_ERROR,
 216                                   (TSTR
 217                                    ("**>>yaffs ecc error unfixed on chunk %d:0"
 218                                     TENDSTR), nand_chunk));
 219                                 dev->n_ecc_unfixed++;
 220                         }
 221
 222                         if (ecc_result2 > 0) {
 223                                 T(YAFFS_TRACE_ERROR,
 224                                   (TSTR
 225                                    ("**>>yaffs ecc error fix performed on chunk %d:1"
 226                                     TENDSTR), nand_chunk));
 227                                 dev->n_ecc_fixed++;
 228                         } else if (ecc_result2 < 0) {
 229                                 T(YAFFS_TRACE_ERROR,
 230                                   (TSTR
 231                                    ("**>>yaffs ecc error unfixed on chunk %d:1"
 232                                     TENDSTR), nand_chunk));
 233                                 dev->n_ecc_unfixed++;
 234                         }
 235
 236                         if (ecc_result1 || ecc_result2) {
 237                                 /* We had a data problem on this page */
 238                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 239                         }
 240
 241                         if (ecc_result1 < 0 || ecc_result2 < 0)
 242                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 243                         else if (ecc_result1 > 0 || ecc_result2 > 0)
 244                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 245                         else
 246                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 247                 }
 248         } else {
 249                 /* Must allocate enough memory for spare+2*sizeof(int) */
 250                 /* for ecc results from device. */
 251                 struct yaffs_nand_spare nspare;
 252
 253                 memset(&nspare, 0, sizeof(nspare));
 254
 255                 ret_val = dev->param.read_chunk_fn(dev, nand_chunk, data,
 256                                         (yaffs_spare *) &nspare);
 257                 memcpy(spare, &nspare, sizeof(yaffs_spare));
 258                 if (data && correct_errors) {
 259                         if (nspare.eccres1 > 0) {
 260                                 T(YAFFS_TRACE_ERROR,
 261                                   (TSTR
 262                                    ("**>>mtd ecc error fix performed on chunk %d:0"
 263                                     TENDSTR), nand_chunk));
 264                         } else if (nspare.eccres1 < 0) {
 265                                 T(YAFFS_TRACE_ERROR,
 266                                   (TSTR
 267                                    ("**>>mtd ecc error unfixed on chunk %d:0"
 268                                     TENDSTR), nand_chunk));
 269                         }
 270
 271                         if (nspare.eccres2 > 0) {
 272                                 T(YAFFS_TRACE_ERROR,
 273                                   (TSTR
 274                                    ("**>>mtd ecc error fix performed on chunk %d:1"
 275                                     TENDSTR), nand_chunk));
 276                         } else if (nspare.eccres2 < 0) {
 277                                 T(YAFFS_TRACE_ERROR,
 278                                   (TSTR
 279                                    ("**>>mtd ecc error unfixed on chunk %d:1"
 280                                     TENDSTR), nand_chunk));
 281                         }
 282
 283                         if (nspare.eccres1 || nspare.eccres2) {
 284                                 /* We had a data problem on this page */
 285                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 286                         }
 287
 288                         if (nspare.eccres1 < 0 || nspare.eccres2 < 0)
 289                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 290                         else if (nspare.eccres1 > 0 || nspare.eccres2 > 0)
 291                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 292                         else
 293                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 294
 295                 }
 296         }
 297         return ret_val;
 298 }
 299
 300 #ifdef NOTYET
 301 static int yaffs_check_chunk_erased(struct yaffs_dev_s *dev,
 302                                   int nand_chunk)
 303 {
 304         static int init;
 305         static __u8 cmpbuf[YAFFS_BYTES_PER_CHUNK];
 306         static __u8 data[YAFFS_BYTES_PER_CHUNK];
 307         /* Might as well always allocate the larger size for */
 308         /* dev->param.use_nand_ecc == true; */
 309         static __u8 spare[sizeof(struct yaffs_nand_spare)];
 310
 311         dev->param.read_chunk_fn(dev, nand_chunk, data, (yaffs_spare *) spare);
 312
 313         if (!init) {
 314                 memset(cmpbuf, 0xff, YAFFS_BYTES_PER_CHUNK);
 315                 init = 1;
 316         }
 317
 318         if (memcmp(cmpbuf, data, YAFFS_BYTES_PER_CHUNK))
 319                 return YAFFS_FAIL;
 320         if (memcmp(cmpbuf, spare, 16))
 321                 return YAFFS_FAIL;
 322
 323         return YAFFS_OK;
 324
 325 }
 326 #endif
 327
 328 /*
 329  * Functions for robustisizing
 330  */
 331
 332 static void yaffs_handle_rd_data_error(yaffs_dev_t *dev, int nand_chunk)
 333 {
 334         int flash_block = nand_chunk / dev->param.chunks_per_block;
 335
 336         /* Mark the block for retirement */
 337         yaffs_get_block_info(dev, flash_block + dev->block_offset)->needs_retiring = 1;
 338         T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
 339           (TSTR("**>>Block %d marked for retirement" TENDSTR), flash_block));
 340
 341         /* TODO:
 342          * Just do a garbage collection on the affected block
 343          * then retire the block
 344          * NB recursion
 345          */
 346 }
 347
 348 #ifdef NOTYET
 349 static void yaffs_check_written_block(yaffs_dev_t *dev, int nand_chunk)
 350 {
 351 }
 352
 353 static void yaffs_handle_chunk_wr_ok(yaffs_dev_t *dev, int nand_chunk,
 354                                      const __u8 *data,
 355                                      const yaffs_spare *spare)
 356 {
 357 }
 358
 359 static void yaffs_handle_chunk_update(yaffs_dev_t *dev, int nand_chunk,
 360                                     const yaffs_spare *spare)
 361 {
 362 }
 363
 364 static void yaffs_handle_chunk_wr_error(yaffs_dev_t *dev, int nand_chunk)
 365 {
 366         int flash_block = nand_chunk / dev->param.chunks_per_block;
 367
 368         /* Mark the block for retirement */
 369         yaffs_get_block_info(dev, flash_block)->needs_retiring = 1;
 370         /* Delete the chunk */
 371         yaffs_chunk_del(dev, nand_chunk, 1, __LINE__);
 372 }
 373
 374 static int yaffs_verify_cmp(const __u8 *d0, const __u8 *d1,
 375                                const yaffs_spare *s0, const yaffs_spare *s1)
 376 {
 377
 378         if (memcmp(d0, d1, YAFFS_BYTES_PER_CHUNK) != 0 ||
 379             s0->tb0 != s1->tb0 ||
 380             s0->tb1 != s1->tb1 ||
 381             s0->tb2 != s1->tb2 ||
 382             s0->tb3 != s1->tb3 ||
 383             s0->tb4 != s1->tb4 ||
 384             s0->tb5 != s1->tb5 ||
 385             s0->tb6 != s1->tb6 ||
 386             s0->tb7 != s1->tb7 ||
 387             s0->ecc1[0] != s1->ecc1[0] ||
 388             s0->ecc1[1] != s1->ecc1[1] ||
 389             s0->ecc1[2] != s1->ecc1[2] ||
 390             s0->ecc2[0] != s1->ecc2[0] ||
 391             s0->ecc2[1] != s1->ecc2[1] || s0->ecc2[2] != s1->ecc2[2]) {
 392                 return 0;
 393         }
 394
 395         return 1;
 396 }
 397 #endif                          /* NOTYET */
 398
 399 int yaffs_tags_compat_wr(yaffs_dev_t *dev,
 400                                                 int nand_chunk,
 401                                                 const __u8 *data,
 402                                                 const yaffs_ext_tags *ext_tags)
 403 {
 404         yaffs_spare spare;
 405         yaffs_tags_t tags;
 406
 407         yaffs_spare_init(&spare);
 408
 409         if (ext_tags->is_deleted)
 410                 spare.page_status = 0;
 411         else {
 412                 tags.obj_id = ext_tags->obj_id;
 413                 tags.chunk_id = ext_tags->chunk_id;
 414
 415                 tags.n_bytes_lsb = ext_tags->n_bytes & 0x3ff;
 416
 417                 if (dev->data_bytes_per_chunk >= 1024)
 418                         tags.n_bytes_msb = (ext_tags->n_bytes >> 10) & 3;
 419                 else
 420                         tags.n_bytes_msb = 3;
 421
 422
 423                 tags.serial_number = ext_tags->serial_number;
 424
 425                 if (!dev->param.use_nand_ecc && data)
 426                         yaffs_calc_ecc(data, &spare);
 427
 428                 yaffs_load_tags_to_spare(&spare, &tags);
 429
 430         }
 431
 432         return yaffs_wr_nand(dev, nand_chunk, data, &spare);
 433 }
 434
 435 int yaffs_tags_compat_rd(yaffs_dev_t *dev,
 436                                                      int nand_chunk,
 437                                                      __u8 *data,
 438                                                      yaffs_ext_tags *ext_tags)
 439 {
 440
 441         yaffs_spare spare;
 442         yaffs_tags_t tags;
 443         yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_UNKNOWN;
 444
 445         static yaffs_spare spare_ff;
 446         static int init;
 447
 448         if (!init) {
 449                 memset(&spare_ff, 0xFF, sizeof(spare_ff));
 450                 init = 1;
 451         }
 452
 453         if (yaffs_rd_chunk_nand
 454             (dev, nand_chunk, data, &spare, &ecc_result, 1)) {
 455                 /* ext_tags may be NULL */
 456                 if (ext_tags) {
 457
 458                         int deleted =
 459                             (yaffs_count_bits(spare.page_status) < 7) ? 1 : 0;
 460
 461                         ext_tags->is_deleted = deleted;
 462                         ext_tags->ecc_result = ecc_result;
 463                         ext_tags->block_bad = 0;        /* We're reading it */
 464                         /* therefore it is not a bad block */
 465                         ext_tags->chunk_used =
 466                             (memcmp(&spare_ff, &spare, sizeof(spare_ff)) !=
 467                              0) ? 1 : 0;
 468
 469                         if (ext_tags->chunk_used) {
 470                                 yaffs_get_tags_from_spare(dev, &spare, &tags);
 471
 472                                 ext_tags->obj_id = tags.obj_id;
 473                                 ext_tags->chunk_id = tags.chunk_id;
 474                                 ext_tags->n_bytes = tags.n_bytes_lsb;
 475
 476                                 if (dev->data_bytes_per_chunk >= 1024)
 477                                         ext_tags->n_bytes |= (((unsigned) tags.n_bytes_msb) << 10);
 478
 479                                 ext_tags->serial_number = tags.serial_number;
 480                         }
 481                 }
 482
 483                 return YAFFS_OK;
 484         } else {
 485                 return YAFFS_FAIL;
 486         }
 487 }
 488
 489 int yaffs_tags_compat_mark_bad(struct yaffs_dev_s *dev,
 490                                             int flash_block)
 491 {
 492
 493         yaffs_spare spare;
 494
 495         memset(&spare, 0xff, sizeof(yaffs_spare));
 496
 497         spare.block_status = 'Y';
 498
 499         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block, NULL,
 500                                &spare);
 501         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block + 1,
 502                                NULL, &spare);
 503
 504         return YAFFS_OK;
 505
 506 }
 507
 508 int yaffs_tags_compat_query_block(struct yaffs_dev_s *dev,
 509                                           int block_no,
 510                                           yaffs_block_state_t *state,
 511                                           __u32 *seq_number)
 512 {
 513
 514         yaffs_spare spare0, spare1;
 515         static yaffs_spare spare_ff;
 516         static int init;
 517         yaffs_ecc_result dummy;
 518
 519         if (!init) {
 520                 memset(&spare_ff, 0xFF, sizeof(spare_ff));
 521                 init = 1;
 522         }
 523
 524         *seq_number = 0;
 525
 526         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block, NULL,
 527                                 &spare0, &dummy, 1);
 528         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block + 1, NULL,
 529                                 &spare1, &dummy, 1);
 530
 531         if (yaffs_count_bits(spare0.block_status & spare1.block_status) < 7)
 532                 *state = YAFFS_BLOCK_STATE_DEAD;
 533         else if (memcmp(&spare_ff, &spare0, sizeof(spare_ff)) == 0)
 534                 *state = YAFFS_BLOCK_STATE_EMPTY;
 535         else
 536                 *state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
 537
 538         return YAFFS_OK;
 539 }