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                 yaffs_trace(YAFFS_TRACE_ERROR,
 136                         "**>> yaffs chunk %d is not valid",
 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) {
 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                                 yaffs_trace(YAFFS_TRACE_ERROR,
 179                                         "**>>yaffs ecc error fix performed on chunk %d:0",
 180                                         nand_chunk);
 181                                 dev->n_ecc_fixed++;
 182                         } else if (ecc_result1 < 0) {
 183                                 yaffs_trace(YAFFS_TRACE_ERROR,
 184                                         "**>>yaffs ecc error unfixed on chunk %d:0",
 185                                         nand_chunk);
 186                                 dev->n_ecc_unfixed++;
 187                         }
 188
 189                         if (ecc_result2 > 0) {
 190                                 yaffs_trace(YAFFS_TRACE_ERROR,
 191                                         "**>>yaffs ecc error fix performed on chunk %d:1",
 192                                         nand_chunk);
 193                                 dev->n_ecc_fixed++;
 194                         } else if (ecc_result2 < 0) {
 195                                 yaffs_trace(YAFFS_TRACE_ERROR,
 196                                         "**>>yaffs ecc error unfixed on chunk %d:1",
 197                                         nand_chunk);
 198                                 dev->n_ecc_unfixed++;
 199                         }
 200
 201                         if (ecc_result1 || ecc_result2) {
 202                                 /* We had a data problem on this page */
 203                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 204                         }
 205
 206                         if (ecc_result1 < 0 || ecc_result2 < 0)
 207                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 208                         else if (ecc_result1 > 0 || ecc_result2 > 0)
 209                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 210                         else
 211                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 212                 }
 213         } else {
 214                 /* Must allocate enough memory for spare+2*sizeof(int) */
 215                 /* for ecc results from device. */
 216                 struct yaffs_nand_spare nspare;
 217
 218                 memset(&nspare, 0, sizeof(nspare));
 219
 220                 ret_val = dev->param.read_chunk_fn(dev, nand_chunk, data,
 221                                                    (struct yaffs_spare *)
 222                                                    &nspare);
 223                 memcpy(spare, &nspare, sizeof(struct yaffs_spare));
 224                 if (data && correct_errors) {
 225                         if (nspare.eccres1 > 0) {
 226                                 yaffs_trace(YAFFS_TRACE_ERROR,
 227                                         "**>>mtd ecc error fix performed on chunk %d:0",
 228                                         nand_chunk);
 229                         } else if (nspare.eccres1 < 0) {
 230                                 yaffs_trace(YAFFS_TRACE_ERROR,
 231                                         "**>>mtd ecc error unfixed on chunk %d:0",
 232                                         nand_chunk);
 233                         }
 234
 235                         if (nspare.eccres2 > 0) {
 236                                 yaffs_trace(YAFFS_TRACE_ERROR,
 237                                         "**>>mtd ecc error fix performed on chunk %d:1",
 238                                         nand_chunk);
 239                         } else if (nspare.eccres2 < 0) {
 240                                 yaffs_trace(YAFFS_TRACE_ERROR,
 241                                         "**>>mtd ecc error unfixed on chunk %d:1",
 242                                         nand_chunk);
 243                         }
 244
 245                         if (nspare.eccres1 || nspare.eccres2) {
 246                                 /* We had a data problem on this page */
 247                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 248                         }
 249
 250                         if (nspare.eccres1 < 0 || nspare.eccres2 < 0)
 251                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 252                         else if (nspare.eccres1 > 0 || nspare.eccres2 > 0)
 253                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 254                         else
 255                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 256
 257                 }
 258         }
 259         return ret_val;
 260 }
 261
 262 /*
 263  * Functions for robustisizing
 264  */
 265
 266 static void yaffs_handle_rd_data_error(struct yaffs_dev *dev, int nand_chunk)
 267 {
 268         int flash_block = nand_chunk / dev->param.chunks_per_block;
 269
 270         /* Mark the block for retirement */
 271         yaffs_get_block_info(dev,
 272                              flash_block + dev->block_offset)->needs_retiring =
 273             1;
 274         yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
 275                 "**>>Block %d marked for retirement",
 276                 flash_block);
 277
 278         /* TODO:
 279          * Just do a garbage collection on the affected block
 280          * then retire the block
 281          * NB recursion
 282          */
 283 }
 284
 285 int yaffs_tags_compat_wr(struct yaffs_dev *dev,
 286                          int nand_chunk,
 287                          const u8 * data, const struct yaffs_ext_tags *ext_tags)
 288 {
 289         struct yaffs_spare spare;
 290         struct yaffs_tags tags;
 291
 292         yaffs_spare_init(&spare);
 293
 294         if (ext_tags->is_deleted)
 295                 spare.page_status = 0;
 296         else {
 297                 tags.obj_id = ext_tags->obj_id;
 298                 tags.chunk_id = ext_tags->chunk_id;
 299
 300                 tags.n_bytes_lsb = ext_tags->n_bytes & 0x3ff;
 301
 302                 if (dev->data_bytes_per_chunk >= 1024)
 303                         tags.n_bytes_msb = (ext_tags->n_bytes >> 10) & 3;
 304                 else
 305                         tags.n_bytes_msb = 3;
 306
 307                 tags.serial_number = ext_tags->serial_number;
 308
 309                 if (!dev->param.use_nand_ecc && data)
 310                         yaffs_calc_ecc(data, &spare);
 311
 312                 yaffs_load_tags_to_spare(&spare, &tags);
 313
 314         }
 315
 316         return yaffs_wr_nand(dev, nand_chunk, data, &spare);
 317 }
 318
 319 int yaffs_tags_compat_rd(struct yaffs_dev *dev,
 320                          int nand_chunk,
 321                          u8 * data, struct yaffs_ext_tags *ext_tags)
 322 {
 323
 324         struct yaffs_spare spare;
 325         struct yaffs_tags tags;
 326         enum yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_UNKNOWN;
 327
 328         static struct yaffs_spare spare_ff;
 329         static int init;
 330
 331         if (!init) {
 332                 memset(&spare_ff, 0xFF, sizeof(spare_ff));
 333                 init = 1;
 334         }
 335
 336         if (yaffs_rd_chunk_nand(dev, nand_chunk, data, &spare, &ecc_result, 1)) {
 337                 /* ext_tags may be NULL */
 338                 if (ext_tags) {
 339
 340                         int deleted =
 341                             (hweight8(spare.page_status) < 7) ? 1 : 0;
 342
 343                         ext_tags->is_deleted = deleted;
 344                         ext_tags->ecc_result = ecc_result;
 345                         ext_tags->block_bad = 0;        /* We're reading it */
 346                         /* therefore it is not a bad block */
 347                         ext_tags->chunk_used =
 348                             (memcmp(&spare_ff, &spare, sizeof(spare_ff)) !=
 349                              0) ? 1 : 0;
 350
 351                         if (ext_tags->chunk_used) {
 352                                 yaffs_get_tags_from_spare(dev, &spare, &tags);
 353
 354                                 ext_tags->obj_id = tags.obj_id;
 355                                 ext_tags->chunk_id = tags.chunk_id;
 356                                 ext_tags->n_bytes = tags.n_bytes_lsb;
 357
 358                                 if (dev->data_bytes_per_chunk >= 1024)
 359                                         ext_tags->n_bytes |=
 360                                             (((unsigned)tags.
 361                                               n_bytes_msb) << 10);
 362
 363                                 ext_tags->serial_number = tags.serial_number;
 364                         }
 365                 }
 366
 367                 return YAFFS_OK;
 368         } else {
 369                 return YAFFS_FAIL;
 370         }
 371 }
 372
 373 int yaffs_tags_compat_mark_bad(struct yaffs_dev *dev, int flash_block)
 374 {
 375
 376         struct yaffs_spare spare;
 377
 378         memset(&spare, 0xff, sizeof(struct yaffs_spare));
 379
 380         spare.block_status = 'Y';
 381
 382         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block, NULL,
 383                       &spare);
 384         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block + 1,
 385                       NULL, &spare);
 386
 387         return YAFFS_OK;
 388
 389 }
 390
 391 int yaffs_tags_compat_query_block(struct yaffs_dev *dev,
 392                                   int block_no,
 393                                   enum yaffs_block_state *state,
 394                                   u32 * seq_number)
 395 {
 396
 397         struct yaffs_spare spare0, spare1;
 398         static struct yaffs_spare spare_ff;
 399         static int init;
 400         enum yaffs_ecc_result dummy;
 401
 402         if (!init) {
 403                 memset(&spare_ff, 0xFF, sizeof(spare_ff));
 404                 init = 1;
 405         }
 406
 407         *seq_number = 0;
 408
 409         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block, NULL,
 410                             &spare0, &dummy, 1);
 411         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block + 1,
 412                             NULL, &spare1, &dummy, 1);
 413
 414         if (hweight8(spare0.block_status & spare1.block_status) < 7)
 415                 *state = YAFFS_BLOCK_STATE_DEAD;
 416         else if (memcmp(&spare_ff, &spare0, sizeof(spare_ff)) == 0)
 417                 *state = YAFFS_BLOCK_STATE_EMPTY;
 418         else
 419                 *state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
 420
 421         return YAFFS_OK;
 422 }