yaffs_tagscompat.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2011 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_calc(data, spare->ecc1);
  28         yaffs_ecc_calc(&data[256], spare->ecc2);
  29 }
  30
  31 void yaffs_calc_tags_ecc(struct yaffs_tags *tags)
  32 {
  33         /* Calculate an ecc */
  34         unsigned char *b = ((union yaffs_tags_union *)tags)->as_bytes;
  35         unsigned i, j;
  36         unsigned ecc = 0;
  37         unsigned bit = 0;
  38
  39         tags->ecc = 0;
  40
  41         for (i = 0; i < 8; i++) {
  42                 for (j = 1; j & 0xff; j <<= 1) {
  43                         bit++;
  44                         if (b[i] & j)
  45                                 ecc ^= bit;
  46                 }
  47         }
  48         tags->ecc = ecc;
  49 }
  50
  51 int yaffs_check_tags_ecc(struct yaffs_tags *tags)
  52 {
  53         unsigned ecc = tags->ecc;
  54
  55         yaffs_calc_tags_ecc(tags);
  56
  57         ecc ^= tags->ecc;
  58
  59         if (ecc && ecc <= 64) {
  60                 /* TODO: Handle the failure better. Retire? */
  61                 unsigned char *b = ((union yaffs_tags_union *)tags)->as_bytes;
  62
  63                 ecc--;
  64
  65                 b[ecc / 8] ^= (1 << (ecc & 7));
  66
  67                 /* Now recvalc the ecc */
  68                 yaffs_calc_tags_ecc(tags);
  69
  70                 return 1;       /* recovered error */
  71         } else if (ecc) {
  72                 /* Wierd ecc failure value */
  73                 /* TODO Need to do somethiong here */
  74                 return -1;      /* unrecovered error */
  75         }
  76         return 0;
  77 }
  78
  79 /********** Tags **********/
  80
  81 static void yaffs_load_tags_to_spare(struct yaffs_spare *spare_ptr,
  82                                      struct yaffs_tags *tags_ptr)
  83 {
  84         union yaffs_tags_union *tu = (union yaffs_tags_union *)tags_ptr;
  85
  86         yaffs_calc_tags_ecc(tags_ptr);
  87
  88         spare_ptr->tb0 = tu->as_bytes[0];
  89         spare_ptr->tb1 = tu->as_bytes[1];
  90         spare_ptr->tb2 = tu->as_bytes[2];
  91         spare_ptr->tb3 = tu->as_bytes[3];
  92         spare_ptr->tb4 = tu->as_bytes[4];
  93         spare_ptr->tb5 = tu->as_bytes[5];
  94         spare_ptr->tb6 = tu->as_bytes[6];
  95         spare_ptr->tb7 = tu->as_bytes[7];
  96 }
  97
  98 static void yaffs_get_tags_from_spare(struct yaffs_dev *dev,
  99                                       struct yaffs_spare *spare_ptr,
 100                                       struct yaffs_tags *tags_ptr)
 101 {
 102         union yaffs_tags_union *tu = (union yaffs_tags_union *)tags_ptr;
 103         int result;
 104
 105         tu->as_bytes[0] = spare_ptr->tb0;
 106         tu->as_bytes[1] = spare_ptr->tb1;
 107         tu->as_bytes[2] = spare_ptr->tb2;
 108         tu->as_bytes[3] = spare_ptr->tb3;
 109         tu->as_bytes[4] = spare_ptr->tb4;
 110         tu->as_bytes[5] = spare_ptr->tb5;
 111         tu->as_bytes[6] = spare_ptr->tb6;
 112         tu->as_bytes[7] = spare_ptr->tb7;
 113
 114         result = yaffs_check_tags_ecc(tags_ptr);
 115         if (result > 0)
 116                 dev->n_tags_ecc_fixed++;
 117         else if (result < 0)
 118                 dev->n_tags_ecc_unfixed++;
 119 }
 120
 121 static void yaffs_spare_init(struct yaffs_spare *spare)
 122 {
 123         memset(spare, 0xff, sizeof(struct yaffs_spare));
 124 }
 125
 126 static int yaffs_wr_nand(struct yaffs_dev *dev,
 127                          int nand_chunk, const u8 *data,
 128                          struct yaffs_spare *spare)
 129 {
 130         if (nand_chunk < dev->param.start_block * dev->param.chunks_per_block) {
 131                 yaffs_trace(YAFFS_TRACE_ERROR,
 132                         "**>> yaffs chunk %d is not valid",
 133                         nand_chunk);
 134                 return YAFFS_FAIL;
 135         }
 136
 137         return dev->param.write_chunk_fn(dev, nand_chunk, data, spare);
 138 }
 139
 140 static int yaffs_rd_chunk_nand(struct yaffs_dev *dev,
 141                                int nand_chunk,
 142                                u8 *data,
 143                                struct yaffs_spare *spare,
 144                                enum yaffs_ecc_result *ecc_result,
 145                                int correct_errors)
 146 {
 147         int ret_val;
 148         struct yaffs_spare local_spare;
 149
 150         if (!spare) {
 151                 /* If we don't have a real spare, then we use a local one. */
 152                 /* Need this for the calculation of the ecc */
 153                 spare = &local_spare;
 154         }
 155
 156         if (!dev->param.use_nand_ecc) {
 157                 ret_val =
 158                     dev->param.read_chunk_fn(dev, nand_chunk, data, spare);
 159                 if (data && correct_errors) {
 160                         /* Do ECC correction */
 161                         /* Todo handle any errors */
 162                         int ecc_result1, ecc_result2;
 163                         u8 calc_ecc[3];
 164
 165                         yaffs_ecc_calc(data, calc_ecc);
 166                         ecc_result1 =
 167                             yaffs_ecc_correct(data, spare->ecc1, calc_ecc);
 168                         yaffs_ecc_calc(&data[256], calc_ecc);
 169                         ecc_result2 =
 170                             yaffs_ecc_correct(&data[256], spare->ecc2,
 171                                               calc_ecc);
 172
 173                         if (ecc_result1 > 0) {
 174                                 yaffs_trace(YAFFS_TRACE_ERROR,
 175                                         "**>>yaffs ecc error fix performed on chunk %d:0",
 176                                         nand_chunk);
 177                                 dev->n_ecc_fixed++;
 178                         } else if (ecc_result1 < 0) {
 179                                 yaffs_trace(YAFFS_TRACE_ERROR,
 180                                         "**>>yaffs ecc error unfixed on chunk %d:0",
 181                                         nand_chunk);
 182                                 dev->n_ecc_unfixed++;
 183                         }
 184
 185                         if (ecc_result2 > 0) {
 186                                 yaffs_trace(YAFFS_TRACE_ERROR,
 187                                         "**>>yaffs ecc error fix performed on chunk %d:1",
 188                                         nand_chunk);
 189                                 dev->n_ecc_fixed++;
 190                         } else if (ecc_result2 < 0) {
 191                                 yaffs_trace(YAFFS_TRACE_ERROR,
 192                                         "**>>yaffs ecc error unfixed on chunk %d:1",
 193                                         nand_chunk);
 194                                 dev->n_ecc_unfixed++;
 195                         }
 196
 197                         if (ecc_result1 || ecc_result2) {
 198                                 /* We had a data problem on this page */
 199                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 200                         }
 201
 202                         if (ecc_result1 < 0 || ecc_result2 < 0)
 203                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 204                         else if (ecc_result1 > 0 || ecc_result2 > 0)
 205                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 206                         else
 207                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 208                 }
 209         } else {
 210                 /* Must allocate enough memory for spare+2*sizeof(int) */
 211                 /* for ecc results from device. */
 212                 struct yaffs_nand_spare nspare;
 213
 214                 memset(&nspare, 0, sizeof(nspare));
 215
 216                 ret_val = dev->param.read_chunk_fn(dev, nand_chunk, data,
 217                                                    (struct yaffs_spare *)
 218                                                    &nspare);
 219                 memcpy(spare, &nspare, sizeof(struct yaffs_spare));
 220                 if (data && correct_errors) {
 221                         if (nspare.eccres1 > 0) {
 222                                 yaffs_trace(YAFFS_TRACE_ERROR,
 223                                         "**>>mtd ecc error fix performed on chunk %d:0",
 224                                         nand_chunk);
 225                         } else if (nspare.eccres1 < 0) {
 226                                 yaffs_trace(YAFFS_TRACE_ERROR,
 227                                         "**>>mtd ecc error unfixed on chunk %d:0",
 228                                         nand_chunk);
 229                         }
 230
 231                         if (nspare.eccres2 > 0) {
 232                                 yaffs_trace(YAFFS_TRACE_ERROR,
 233                                         "**>>mtd ecc error fix performed on chunk %d:1",
 234                                         nand_chunk);
 235                         } else if (nspare.eccres2 < 0) {
 236                                 yaffs_trace(YAFFS_TRACE_ERROR,
 237                                         "**>>mtd ecc error unfixed on chunk %d:1",
 238                                         nand_chunk);
 239                         }
 240
 241                         if (nspare.eccres1 || nspare.eccres2) {
 242                                 /* We had a data problem on this page */
 243                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 244                         }
 245
 246                         if (nspare.eccres1 < 0 || nspare.eccres2 < 0)
 247                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 248                         else if (nspare.eccres1 > 0 || nspare.eccres2 > 0)
 249                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 250                         else
 251                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 252
 253                 }
 254         }
 255         return ret_val;
 256 }
 257
 258 /*
 259  * Functions for robustisizing
 260  */
 261
 262 static void yaffs_handle_rd_data_error(struct yaffs_dev *dev, int nand_chunk)
 263 {
 264         int flash_block = nand_chunk / dev->param.chunks_per_block;
 265
 266         /* Mark the block for retirement */
 267         yaffs_get_block_info(dev, flash_block + dev->block_offset)->
 268                 needs_retiring = 1;
 269         yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
 270                 "**>>Block %d marked for retirement",
 271                 flash_block);
 272
 273         /* TODO:
 274          * Just do a garbage collection on the affected block
 275          * then retire the block
 276          * NB recursion
 277          */
 278 }
 279
 280 int yaffs_tags_compat_wr(struct yaffs_dev *dev,
 281                          int nand_chunk,
 282                          const u8 *data, const struct yaffs_ext_tags *ext_tags)
 283 {
 284         struct yaffs_spare spare;
 285         struct yaffs_tags tags;
 286
 287         yaffs_spare_init(&spare);
 288
 289         if (ext_tags->is_deleted)
 290                 spare.page_status = 0;
 291         else {
 292                 tags.obj_id = ext_tags->obj_id;
 293                 tags.chunk_id = ext_tags->chunk_id;
 294
 295                 tags.n_bytes_lsb = ext_tags->n_bytes & (1024 - 1);
 296
 297                 if (dev->data_bytes_per_chunk >= 1024)
 298                         tags.n_bytes_msb = (ext_tags->n_bytes >> 10) & 3;
 299                 else
 300                         tags.n_bytes_msb = 3;
 301
 302                 tags.serial_number = ext_tags->serial_number;
 303
 304                 if (!dev->param.use_nand_ecc && data)
 305                         yaffs_calc_ecc(data, &spare);
 306
 307                 yaffs_load_tags_to_spare(&spare, &tags);
 308         }
 309         return yaffs_wr_nand(dev, nand_chunk, data, &spare);
 310 }
 311
 312 int yaffs_tags_compat_rd(struct yaffs_dev *dev,
 313                          int nand_chunk,
 314                          u8 *data, struct yaffs_ext_tags *ext_tags)
 315 {
 316         struct yaffs_spare spare;
 317         struct yaffs_tags tags;
 318         enum yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_UNKNOWN;
 319         static struct yaffs_spare spare_ff;
 320         static int init;
 321         int deleted;
 322
 323         if (!init) {
 324                 memset(&spare_ff, 0xff, sizeof(spare_ff));
 325                 init = 1;
 326         }
 327
 328         if (!yaffs_rd_chunk_nand(dev, nand_chunk,
 329                                         data, &spare, &ecc_result, 1))
 330                 return YAFFS_FAIL;
 331
 332         /* ext_tags may be NULL */
 333         if (!ext_tags)
 334                 return YAFFS_OK;
 335
 336         deleted = (hweight8(spare.page_status) < 7) ? 1 : 0;
 337
 338         ext_tags->is_deleted = deleted;
 339         ext_tags->ecc_result = ecc_result;
 340         ext_tags->block_bad = 0;        /* We're reading it */
 341         /* therefore it is not a bad block */
 342         ext_tags->chunk_used =
 343                 memcmp(&spare_ff, &spare, sizeof(spare_ff)) ? 1 : 0;
 344
 345         if (ext_tags->chunk_used) {
 346                 yaffs_get_tags_from_spare(dev, &spare, &tags);
 347                 ext_tags->obj_id = tags.obj_id;
 348                 ext_tags->chunk_id = tags.chunk_id;
 349                 ext_tags->n_bytes = tags.n_bytes_lsb;
 350
 351                 if (dev->data_bytes_per_chunk >= 1024)
 352                         ext_tags->n_bytes |=
 353                                 (((unsigned)tags.n_bytes_msb) << 10);
 354
 355                 ext_tags->serial_number = tags.serial_number;
 356         }
 357
 358         return YAFFS_OK;
 359 }
 360
 361 int yaffs_tags_compat_mark_bad(struct yaffs_dev *dev, int flash_block)
 362 {
 363         struct yaffs_spare spare;
 364
 365         memset(&spare, 0xff, sizeof(struct yaffs_spare));
 366
 367         spare.block_status = 'Y';
 368
 369         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block, NULL,
 370                       &spare);
 371         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block + 1,
 372                       NULL, &spare);
 373
 374         return YAFFS_OK;
 375 }
 376
 377 int yaffs_tags_compat_query_block(struct yaffs_dev *dev,
 378                                   int block_no,
 379                                   enum yaffs_block_state *state,
 380                                   u32 *seq_number)
 381 {
 382         struct yaffs_spare spare0, spare1;
 383         static struct yaffs_spare spare_ff;
 384         static int init;
 385         enum yaffs_ecc_result dummy;
 386
 387         if (!init) {
 388                 memset(&spare_ff, 0xff, sizeof(spare_ff));
 389                 init = 1;
 390         }
 391
 392         *seq_number = 0;
 393
 394         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block, NULL,
 395                             &spare0, &dummy, 1);
 396         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block + 1,
 397                             NULL, &spare1, &dummy, 1);
 398
 399         if (hweight8(spare0.block_status & spare1.block_status) < 7)
 400                 *state = YAFFS_BLOCK_STATE_DEAD;
 401         else if (memcmp(&spare_ff, &spare0, sizeof(spare_ff)) == 0)
 402                 *state = YAFFS_BLOCK_STATE_EMPTY;
 403         else
 404                 *state = YAFFS_BLOCK_STATE_NEEDS_SCAN;
 405
 406         return YAFFS_OK;
 407 }