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 static 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         int data_size;
 131         int spare_size;
 132         u8 spare_buffer[100];
 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         /* Format up the spare */
 142
 143         return dev->param.drv_write_chunk_fn(dev, nand_chunk,
 144                                 data, data_size,
 145                                 spare_buffer, spare_size);
 146 }
 147
 148 static int yaffs_rd_chunk_nand(struct yaffs_dev *dev,
 149                                int nand_chunk,
 150                                u8 *data,
 151                                struct yaffs_spare *spare,
 152                                enum yaffs_ecc_result *ecc_result,
 153                                int correct_errors)
 154 {
 155         int ret_val;
 156         struct yaffs_spare local_spare;
 157         int data_size;
 158         int spare_size;
 159
 160         if (!spare) {
 161                 /* If we don't have a real spare, then we use a local one. */
 162                 /* Need this for the calculation of the ecc */
 163                 spare = &local_spare;
 164         }
 165
 166         if (!dev->param.use_nand_ecc) {
 167                 ret_val =
 168                     dev->param.drv_read_chunk_fn(dev, nand_chunk,
 169                                                  data, data_size,
 170                                                  (u8 *)spare, spare_size,
 171                                         ecc_result);
 172                 if (data && correct_errors) {
 173                         /* Do ECC correction */
 174                         /* Todo handle any errors */
 175                         int ecc_result1, ecc_result2;
 176                         u8 calc_ecc[3];
 177
 178                         yaffs_ecc_calc(data, calc_ecc);
 179                         ecc_result1 =
 180                             yaffs_ecc_correct(data, spare->ecc1, calc_ecc);
 181                         yaffs_ecc_calc(&data[256], calc_ecc);
 182                         ecc_result2 =
 183                             yaffs_ecc_correct(&data[256], spare->ecc2,
 184                                               calc_ecc);
 185
 186                         if (ecc_result1 > 0) {
 187                                 yaffs_trace(YAFFS_TRACE_ERROR,
 188                                         "**>>yaffs ecc error fix performed on chunk %d:0",
 189                                         nand_chunk);
 190                                 dev->n_ecc_fixed++;
 191                         } else if (ecc_result1 < 0) {
 192                                 yaffs_trace(YAFFS_TRACE_ERROR,
 193                                         "**>>yaffs ecc error unfixed on chunk %d:0",
 194                                         nand_chunk);
 195                                 dev->n_ecc_unfixed++;
 196                         }
 197
 198                         if (ecc_result2 > 0) {
 199                                 yaffs_trace(YAFFS_TRACE_ERROR,
 200                                         "**>>yaffs ecc error fix performed on chunk %d:1",
 201                                         nand_chunk);
 202                                 dev->n_ecc_fixed++;
 203                         } else if (ecc_result2 < 0) {
 204                                 yaffs_trace(YAFFS_TRACE_ERROR,
 205                                         "**>>yaffs ecc error unfixed on chunk %d:1",
 206                                         nand_chunk);
 207                                 dev->n_ecc_unfixed++;
 208                         }
 209
 210                         if (ecc_result1 || ecc_result2) {
 211                                 /* We had a data problem on this page */
 212                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 213                         }
 214
 215                         if (ecc_result1 < 0 || ecc_result2 < 0)
 216                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 217                         else if (ecc_result1 > 0 || ecc_result2 > 0)
 218                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 219                         else
 220                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 221                 }
 222         } else {
 223                 /* Must allocate enough memory for spare+2*sizeof(int) */
 224                 /* for ecc results from device. */
 225                 struct yaffs_nand_spare nspare;
 226
 227                 memset(&nspare, 0, sizeof(nspare));
 228
 229                 ret_val = dev->param.drv_read_chunk_fn(dev, nand_chunk,
 230                                                 data, data_size,
 231                                                 (u8 *) &nspare, sizeof(nspare),
 232                                                 NULL);
 233                 memcpy(spare, &nspare, sizeof(struct yaffs_spare));
 234                 if (data && correct_errors) {
 235                         if (nspare.eccres1 > 0) {
 236                                 yaffs_trace(YAFFS_TRACE_ERROR,
 237                                         "**>>mtd ecc error fix performed on chunk %d:0",
 238                                         nand_chunk);
 239                         } else if (nspare.eccres1 < 0) {
 240                                 yaffs_trace(YAFFS_TRACE_ERROR,
 241                                         "**>>mtd ecc error unfixed on chunk %d:0",
 242                                         nand_chunk);
 243                         }
 244
 245                         if (nspare.eccres2 > 0) {
 246                                 yaffs_trace(YAFFS_TRACE_ERROR,
 247                                         "**>>mtd ecc error fix performed on chunk %d:1",
 248                                         nand_chunk);
 249                         } else if (nspare.eccres2 < 0) {
 250                                 yaffs_trace(YAFFS_TRACE_ERROR,
 251                                         "**>>mtd ecc error unfixed on chunk %d:1",
 252                                         nand_chunk);
 253                         }
 254
 255                         if (nspare.eccres1 || nspare.eccres2) {
 256                                 /* We had a data problem on this page */
 257                                 yaffs_handle_rd_data_error(dev, nand_chunk);
 258                         }
 259
 260                         if (nspare.eccres1 < 0 || nspare.eccres2 < 0)
 261                                 *ecc_result = YAFFS_ECC_RESULT_UNFIXED;
 262                         else if (nspare.eccres1 > 0 || nspare.eccres2 > 0)
 263                                 *ecc_result = YAFFS_ECC_RESULT_FIXED;
 264                         else
 265                                 *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
 266
 267                 }
 268         }
 269         return ret_val;
 270 }
 271
 272 /*
 273  * Functions for robustisizing
 274  */
 275
 276 static void yaffs_handle_rd_data_error(struct yaffs_dev *dev, int nand_chunk)
 277 {
 278         int flash_block = nand_chunk / dev->param.chunks_per_block;
 279
 280         /* Mark the block for retirement */
 281         yaffs_get_block_info(dev, flash_block + dev->block_offset)->
 282                 needs_retiring = 1;
 283         yaffs_trace(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
 284                 "**>>Block %d marked for retirement",
 285                 flash_block);
 286
 287         /* TODO:
 288          * Just do a garbage collection on the affected block
 289          * then retire the block
 290          * NB recursion
 291          */
 292 }
 293
 294 static int yaffs_tags_compat_wr(struct yaffs_dev *dev,
 295                          int nand_chunk,
 296                          const u8 *data, const struct yaffs_ext_tags *ext_tags)
 297 {
 298         struct yaffs_spare spare;
 299         struct yaffs_tags tags;
 300
 301         yaffs_spare_init(&spare);
 302
 303         if (ext_tags->is_deleted)
 304                 spare.page_status = 0;
 305         else {
 306                 tags.obj_id = ext_tags->obj_id;
 307                 tags.chunk_id = ext_tags->chunk_id;
 308
 309                 tags.n_bytes_lsb = ext_tags->n_bytes & (1024 - 1);
 310
 311                 if (dev->data_bytes_per_chunk >= 1024)
 312                         tags.n_bytes_msb = (ext_tags->n_bytes >> 10) & 3;
 313                 else
 314                         tags.n_bytes_msb = 3;
 315
 316                 tags.serial_number = ext_tags->serial_number;
 317
 318                 if (!dev->param.use_nand_ecc && data)
 319                         yaffs_calc_ecc(data, &spare);
 320
 321                 yaffs_load_tags_to_spare(&spare, &tags);
 322         }
 323         return yaffs_wr_nand(dev, nand_chunk, data, &spare);
 324 }
 325
 326 static int yaffs_tags_compat_rd(struct yaffs_dev *dev,
 327                          int nand_chunk,
 328                          u8 *data, struct yaffs_ext_tags *ext_tags)
 329 {
 330         struct yaffs_spare spare;
 331         struct yaffs_tags tags;
 332         enum yaffs_ecc_result ecc_result = YAFFS_ECC_RESULT_UNKNOWN;
 333         static struct yaffs_spare spare_ff;
 334         static int init;
 335         int deleted;
 336
 337         if (!init) {
 338                 memset(&spare_ff, 0xff, sizeof(spare_ff));
 339                 init = 1;
 340         }
 341
 342         if (!yaffs_rd_chunk_nand(dev, nand_chunk,
 343                                         data, &spare, &ecc_result, 1))
 344                 return YAFFS_FAIL;
 345
 346         /* ext_tags may be NULL */
 347         if (!ext_tags)
 348                 return YAFFS_OK;
 349
 350         deleted = (hweight8(spare.page_status) < 7) ? 1 : 0;
 351
 352         ext_tags->is_deleted = deleted;
 353         ext_tags->ecc_result = ecc_result;
 354         ext_tags->block_bad = 0;        /* We're reading it */
 355         /* therefore it is not a bad block */
 356         ext_tags->chunk_used =
 357                 memcmp(&spare_ff, &spare, sizeof(spare_ff)) ? 1 : 0;
 358
 359         if (ext_tags->chunk_used) {
 360                 yaffs_get_tags_from_spare(dev, &spare, &tags);
 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.n_bytes_msb) << 10);
 368
 369                 ext_tags->serial_number = tags.serial_number;
 370         }
 371
 372         return YAFFS_OK;
 373 }
 374
 375 static int yaffs_tags_compat_mark_bad(struct yaffs_dev *dev, int flash_block)
 376 {
 377         struct yaffs_spare spare;
 378
 379         memset(&spare, 0xff, sizeof(struct yaffs_spare));
 380
 381         spare.block_status = 'Y';
 382
 383         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block, NULL,
 384                       &spare);
 385         yaffs_wr_nand(dev, flash_block * dev->param.chunks_per_block + 1,
 386                       NULL, &spare);
 387
 388         return YAFFS_OK;
 389 }
 390
 391 static 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         struct yaffs_spare spare0, spare1;
 397         static struct yaffs_spare spare_ff;
 398         static int init;
 399         enum yaffs_ecc_result dummy;
 400
 401         if (!init) {
 402                 memset(&spare_ff, 0xff, sizeof(spare_ff));
 403                 init = 1;
 404         }
 405
 406         *seq_number = 0;
 407
 408         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block, NULL,
 409                             &spare0, &dummy, 1);
 410         yaffs_rd_chunk_nand(dev, block_no * dev->param.chunks_per_block + 1,
 411                             NULL, &spare1, &dummy, 1);
 412
 413         if (hweight8(spare0.block_status & spare1.block_status) < 7)
 414                 *state = YAFFS_BLOCK_STATE_DEAD;
 415         else if (memcmp(&spare_ff, &spare0, sizeof(spare_ff)) == 0)
 416                 *state = YAFFS_BLOCK_STATE_EMPTY;
 417         else
 418                 *state = YAFFS_BLOCK_STATE_NEEDS_SCAN;
 419
 420         return YAFFS_OK;
 421 }
 422
 423 void yaffs_tags_compat_install(struct yaffs_dev *dev)
 424 {
 425         if(dev->param.is_yaffs2)
 426                 return;
 427         if(!dev->param.write_chunk_tags_fn)
 428                 dev->param.write_chunk_tags_fn = yaffs_tags_compat_wr;
 429         if(!dev->param.read_chunk_tags_fn)
 430                 dev->param.read_chunk_tags_fn = yaffs_tags_compat_rd;
 431         if(!dev->param.read_chunk_tags_fn)
 432                 dev->param.query_block_fn = yaffs_tags_compat_query_block;
 433         if(!dev->param.mark_bad_fn)
 434                 dev->param.mark_bad_fn = yaffs_tags_compat_mark_bad;
 435 }