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(struct yaffs_dev *dev, int nand_chunk);
  21
  22
  23 /********** Tags ECC calculations  *********/
  24
  25 void yaffs_calc_ecc(const u8 * data, struct yaffs_spare *spare)
  26 {
  27         yaffs_ecc_cacl(data, spare->ecc1);
  28         yaffs_ecc_cacl(&data[256], spare->ecc2);
  29 }
  30
  31 void yaffs_calc_tags_ecc(struct yaffs_tags *tags)
  32 {
  33         /* Calculate an ecc */
  34
  35         unsigned char *b = ((union yaffs_tags_union *)tags)->as_bytes;
  36         unsigned i, j;
  37         unsigned ecc = 0;
  38         unsigned bit = 0;
  39
  40         tags->ecc = 0;
  41
  42         for (i = 0; i < 8; i++) {
  43                 for (j = 1; j & 0xff; j <<= 1) {
  44                         bit++;
  45                         if (b[i] & j)
  46                                 ecc ^= bit;
  47                 }
  48         }
  49
  50         tags->ecc = ecc;
  51
  52 }
  53
  54 int yaffs_check_tags_ecc(struct yaffs_tags *tags)
  55 {
  56         unsigned ecc = tags->ecc;
  57
  58         yaffs_calc_tags_ecc(tags);
  59
  60         ecc ^= tags->ecc;
  61
  62         if (ecc && ecc <= 64) {
  63                 /* TODO: Handle the failure better. Retire? */
  64                 unsigned char *b = ((union yaffs_tags_union *)tags)->as_bytes;
  65
  66                 ecc--;
  67
  68                 b[ecc / 8] ^= (1 << (ecc & 7));
  69
  70                 /* Now recvalc the ecc */
  71                 yaffs_calc_tags_ecc(tags);
  72
  73                 return 1;       /* recovered error */
  74         } else if (ecc) {
  75                 /* Wierd ecc failure value */
  76                 /* TODO Need to do somethiong here */
  77                 return -1;      /* unrecovered error */
  78         }
  79
  80         return 0;
  81 }
  82
  83 /********** Tags **********/
  84
  85 static void yaffs_load_tags_to_spare(struct yaffs_spare *spare_ptr,
  86                                      struct yaffs_tags *tags_ptr)
  87 {
  88         union yaffs_tags_union *tu = (union yaffs_tags_union *)tags_ptr;
  89
  90         yaffs_calc_tags_ecc(tags_ptr);
  91
  92         spare_ptr->tb0 = tu->as_bytes[0];
  93         spare_ptr->tb1 = tu->as_bytes[1];
  94         spare_ptr->tb2 = tu->as_bytes[2];
  95         spare_ptr->tb3 = tu->as_bytes[3];
  96         spare_ptr->tb4 = tu->as_bytes[4];
  97         spare_ptr->tb5 = tu->as_bytes[5];
  98         spare_ptr->tb6 = tu->as_bytes[6];
  99         spare_ptr->tb7 = tu->as_bytes[7];
 100 }
 101
 102 static void yaffs_get_tags_from_spare(struct yaffs_dev *dev,
 103                                       struct yaffs_spare *spare_ptr,
 104                                       struct yaffs_tags *tags_ptr)
 105 {
 106         union yaffs_tags_union *tu = (union yaffs_tags_union *)tags_ptr;
 107         int result;
 108
 109         tu->as_bytes[0] = spare_ptr->tb0;
 110         tu->as_bytes[1] = spare_ptr->tb1;
 111         tu->as_bytes[2] = spare_ptr->tb2;
 112         tu->as_bytes[3] = spare_ptr->tb3;
 113         tu->as_bytes[4] = spare_ptr->tb4;
 114         tu->as_bytes[5] = spare_ptr->tb5;
 115         tu->as_bytes[6] = spare_ptr->tb6;
 116         tu->as_bytes[7] = spare_ptr->tb7;
 117
 118         result = yaffs_check_tags_ecc(tags_ptr);
 119         if (result > 0)
 120                 dev->n_tags_ecc_fixed++;
 121         else if (result < 0)
 122                 dev->n_tags_ecc_unfixed++;
 123 }
 124
 125 static void yaffs_spare_init(struct yaffs_spare *spare)
 126 {
 127         memset(spare, 0xFF, sizeof(struct yaffs_spare));
 128 }
 129
 130 static int yaffs_wr_nand(struct yaffs_dev *dev,
 131                          int nand_chunk, const u8 * data,
 132                          struct yaffs_spare *spare)
 133 {
 134         if (nand_chunk < dev->param.start_block * dev->param.chunks_per_block) {
 135                 T(YAFFS_TRACE_ERROR,
 136                   (TSTR("**>> yaffs chunk %d is not valid" TENDSTR),
 137                    nand_chunk));
 138                 return YAFFS_FAIL;
 139         }
 140
 141         return dev->param.write_chunk_fn(dev, nand_chunk, data, spare);
 142 }
 143
 144 static int yaffs_rd_chunk_nand(struct yaffs_dev *dev,
 145                                int nand_chunk,
 146                                u8 * data,
 147                                struct yaffs_spare *spare,
 148                                enum yaffs_ecc_result *ecc_result,
 149                                int correct_errors)
 150 {
 151         int ret_val;
 152         struct yaffs_spare local_spare;
 153
 154         if (!spare && data) {
 155                 /* If we don't have a real spare, then we use a local one. */
 156                 /* Need this for the calculation of the ecc */
 157                 spare = &local_spare;
 158         }
 159
 160         if (!dev->param.use_nand_ecc) {
 161                 ret_val =
 162                     dev->param.read_chunk_fn(dev, nand_chunk, data, spare);
 163                 if (data && correct_errors) {
 164                         /* Do ECC correction */
 165                         /* Todo handle any errors */
 166                         int ecc_result1, ecc_result2;
 167                         u8 calc_ecc[3];
 168
 169                         yaffs_ecc_cacl(data, calc_ecc);
 170                         ecc_result1 =
 171                             yaffs_ecc_correct(data, spare->ecc1, calc_ecc);
 172                         yaffs_ecc_cacl(&data[256], calc_ecc);
 173                         ecc_result2 =
 174                             yaffs_ecc_correct(&data[256], spare->ecc2,
 175                                               calc_ecc);
 176
 177                         if (ecc_result1 > 0) {
 178                                 T(YAFFS_TRACE_ERROR,
 179                                   (TSTR
 180                                    ("**>>yaffs ecc error fix performed on chunk %d:0"
 181                                     TENDSTR), nand_chunk));
 182                                 dev->n_ecc_fixed++;
 183                         } else if (ecc_result1 < 0) {
 184                                 T(YAFFS_TRACE_ERROR,
 185                                   (TSTR
 186                                    ("**>>yaffs ecc error unfixed on chunk %d:0"
 187                                     TENDSTR), nand_chunk));
 188                                 dev->n_ecc_unfixed++;
 189                         }
 190
 191                         if (ecc_result2 > 0) {
 192                                 T(YAFFS_TRACE_ERROR,
 193                                   (TSTR
 194                                    ("**>>yaffs ecc error fix performed on chunk %d:1"
 195                                     TENDSTR), nand_chunk));
 196                                 dev->n_ecc_fixed++;
 197                         } else if (ecc_result2 < 0) {
 198                                 T(YAFFS_TRACE_ERROR,
 199                                   (TSTR
 200                                    ("**>>yaffs ecc error unfixed on chunk %d:1"
 201                                     TENDSTR), nand_chunk));
 202                                 dev->n_ecc_unfixed++;
 203                         }
 204
 205                         if (ecc_result1 || ecc_result2) {
 206                                 /* We had a data problem on this page */
 207                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 208                         }
 209
 210                         if (ecc_result1 < 0 || ecc_result2 < 0)
 211                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 212                         else if (ecc_result1 > 0 || ecc_result2 > 0)
 213                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 214                         else
 215                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 216                 }
 217         } else {
 218                 /* Must allocate enough memory for spare+2*sizeof(int) */
 219                 /* for ecc results from device. */
 220                 struct yaffs_nand_spare nspare;
 221
 222                 memset(&nspare, 0, sizeof(nspare));
 223
 224                 ret_val = dev->param.read_chunk_fn(dev, nand_chunk, data,
 225                                                    (struct yaffs_spare *)
 226                                                    &nspare);
 227                 memcpy(spare, &nspare, sizeof(struct yaffs_spare));
 228                 if (data && correct_errors) {
 229                         if (nspare.eccres1 > 0) {
 230                                 T(YAFFS_TRACE_ERROR,
 231                                   (TSTR
 232                                    ("**>>mtd ecc error fix performed on chunk %d:0"
 233                                     TENDSTR), nand_chunk));
 234                         } else if (nspare.eccres1 < 0) {
 235                                 T(YAFFS_TRACE_ERROR,
 236                                   (TSTR
 237                                    ("**>>mtd ecc error unfixed on chunk %d:0"
 238                                     TENDSTR), nand_chunk));
 239                         }
 240
 241                         if (nspare.eccres2 > 0) {
 242                                 T(YAFFS_TRACE_ERROR,
 243                                   (TSTR
 244                                    ("**>>mtd ecc error fix performed on chunk %d:1"
 245                                     TENDSTR), nand_chunk));
 246                         } else if (nspare.eccres2 < 0) {
 247                                 T(YAFFS_TRACE_ERROR,
 248                                   (TSTR
 249                                    ("**>>mtd ecc error unfixed on chunk %d:1"
 250                                     TENDSTR), nand_chunk));
 251                         }
 252
 253                         if (nspare.eccres1 || nspare.eccres2) {
 254                                 /* We had a data problem on this page */
 255                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 256                         }
 257
 258                         if (nspare.eccres1 < 0 || nspare.eccres2 < 0)
 259                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 260                         else if (nspare.eccres1 > 0 || nspare.eccres2 > 0)
 261                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 262                         else
 263                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 264
 265                 }
 266         }
 267         return ret_val;
 268 }
 269
 270 /*
 271  * Functions for robustisizing
 272  */
 273
 274 static void yaffs_handle_rd_data_error(struct yaffs_dev *dev, int nand_chunk)
 275 {
 276         int flash_block = nand_chunk / dev->param.chunks_per_block;
 277
 278         /* Mark the block for retirement */
 279         yaffs_get_block_info(dev,
 280                              flash_block + dev->block_offset)->needs_retiring =
 281             1;
 282         T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
 283           (TSTR("**>>Block %d marked for retirement" TENDSTR), flash_block));
 284
 285         /* TODO:
 286          * Just do a garbage collection on the affected block
 287          * then retire the block
 288          * NB recursion
 289          */
 290 }
 291
 292 int yaffs_tags_compat_wr(struct yaffs_dev *dev,
 293                          int nand_chunk,
 294                          const u8 * data, const struct yaffs_ext_tags *ext_tags)
 295 {
 296         struct yaffs_spare spare;
 297         struct yaffs_tags tags;
 298
 299         yaffs_spare_init(&spare);
 300
 301         if (ext_tags->is_deleted)
 302                 spare.page_status = 0;
 303         else {
 304                 tags.obj_id = ext_tags->obj_id;
 305                 tags.chunk_id = ext_tags->chunk_id;
 306
 307                 tags.n_bytes_lsb = ext_tags->n_bytes & 0x3ff;
 308
 309                 if (dev->data_bytes_per_chunk >= 1024)
 310                         tags.n_bytes_msb = (ext_tags->n_bytes >> 10) & 3;
 311                 else
 312                         tags.n_bytes_msb = 3;
 313
 314                 tags.serial_number = ext_tags->serial_number;
 315
 316                 if (!dev->param.use_nand_ecc && data)
 317                         yaffs_calc_ecc(data, &spare);
 318
 319                 yaffs_load_tags_to_spare(&spare, &tags);
 320
 321         }
 322
 323         return yaffs_wr_nand(dev, nand_chunk, data, &spare);
 324 }
 325
 326 int yaffs_tags_compat_rd(struct yaffs_dev *dev,
 327                          int nand_chunk,
 328                          u8 * data, struct yaffs_ext_tags *ext_tags)
 329 {
 330
 331         struct yaffs_spare spare;
 332         struct yaffs_tags tags;
 333         enum yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_UNKNOWN;
 334
 335         static struct yaffs_spare spare_ff;
 336         static int init;
 337
 338         if (!init) {
 339                 memset(&spare_ff, 0xFF, sizeof(spare_ff));
 340                 init = 1;
 341         }
 342
 343         if (yaffs_rd_chunk_nand(dev, nand_chunk, data, &spare, &ecc_result, 1)) {
 344                 /* ext_tags may be NULL */
 345                 if (ext_tags) {
 346
 347                         int deleted =
 348                             (hweight8(spare.page_status) < 7) ? 1 : 0;
 349
 350                         ext_tags->is_deleted = deleted;
 351                         ext_tags->ecc_result = ecc_result;
 352                         ext_tags->block_bad = 0;        /* We're reading it */
 353                         /* therefore it is not a bad block */
 354                         ext_tags->chunk_used =
 355                             (memcmp(&spare_ff, &spare, sizeof(spare_ff)) !=
 356                              0) ? 1 : 0;
 357
 358                         if (ext_tags->chunk_used) {
 359                                 yaffs_get_tags_from_spare(dev, &spare, &tags);
 360
 361                                 ext_tags->obj_id = tags.obj_id;
 362                                 ext_tags->chunk_id = tags.chunk_id;
 363                                 ext_tags->n_bytes = tags.n_bytes_lsb;
 364
 365                                 if (dev->data_bytes_per_chunk >= 1024)
 366                                         ext_tags->n_bytes |=
 367                                             (((unsigned)tags.
 368                                               n_bytes_msb) << 10);
 369
 370                                 ext_tags->serial_number = tags.serial_number;
 371                         }
 372                 }
 373
 374                 return YAFFS_OK;
 375         } else {
 376                 return YAFFS_FAIL;
 377         }
 378 }
 379
 380 int yaffs_tags_compat_mark_bad(struct yaffs_dev *dev, int flash_block)
 381 {
 382
 383         struct yaffs_spare spare;
 384
 385         memset(&spare, 0xff, sizeof(struct yaffs_spare));
 386
 387         spare.block_status = 'Y';
 388
 389         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block, NULL,
 390                       &spare);
 391         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block + 1,
 392                       NULL, &spare);
 393
 394         return YAFFS_OK;
 395
 396 }
 397
 398 int yaffs_tags_compat_query_block(struct yaffs_dev *dev,
 399                                   int block_no,
 400                                   enum yaffs_block_state *state,
 401                                   u32 * seq_number)
 402 {
 403
 404         struct yaffs_spare spare0, spare1;
 405         static struct yaffs_spare spare_ff;
 406         static int init;
 407         enum yaffs_ecc_result dummy;
 408
 409         if (!init) {
 410                 memset(&spare_ff, 0xFF, sizeof(spare_ff));
 411                 init = 1;
 412         }
 413
 414         *seq_number = 0;
 415
 416         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block, NULL,
 417                             &spare0, &dummy, 1);
 418         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block + 1,
 419                             NULL, &spare1, &dummy, 1);
 420
 421         if (hweight8(spare0.block_status & spare1.block_status) < 7)
 422                 *state = YAFFS_BLOCK_STATE_DEAD;
 423         else if (memcmp(&spare_ff, &spare0, sizeof(spare_ff)) == 0)
 424                 *state = YAFFS_BLOCK_STATE_EMPTY;
 425         else
 426                 *state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
 427
 428         return YAFFS_OK;
 429 }