drivers/mtd/onenand/onenand_bbt.c

   1 /*
   2  *  linux/drivers/mtd/onenand/onenand_bbt.c
   3  *
   4  *  Bad Block Table support for the OneNAND driver
   5  *
   6  *  Copyright(c) 2005-2008 Samsung Electronics
   7  *  Kyungmin Park <kyungmin.park@samsung.com>
   8  *
   9  *  TODO:
  10  *    Split BBT core and chip specific BBT.
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  */
  16
  17 #include <common.h>
  18 #include <linux/compat.h>
  19 #include <linux/mtd/mtd.h>
  20 #include <linux/mtd/onenand.h>
  21 #include <malloc.h>
  22
  23 #include <linux/errno.h>
  24
  25 /**
  26  * check_short_pattern - [GENERIC] check if a pattern is in the buffer
  27  * @param buf           the buffer to search
  28  * @param len           the length of buffer to search
  29  * @param paglen        the pagelength
  30  * @param td            search pattern descriptor
  31  *
  32  * Check for a pattern at the given place. Used to search bad block
  33  * tables and good / bad block identifiers. Same as check_pattern, but
  34  * no optional empty check and the pattern is expected to start
  35  * at offset 0.
  36  */
  37 static int check_short_pattern(uint8_t * buf, int len, int paglen,
  38                                struct nand_bbt_descr *td)
  39 {
  40         int i;
  41         uint8_t *p = buf;
  42
  43         /* Compare the pattern */
  44         for (i = 0; i < td->len; i++) {
  45                 if (p[i] != td->pattern[i])
  46                         return -1;
  47         }
  48         return 0;
  49 }
  50
  51 /**
  52  * create_bbt - [GENERIC] Create a bad block table by scanning the device
  53  * @param mtd           MTD device structure
  54  * @param buf           temporary buffer
  55  * @param bd            descriptor for the good/bad block search pattern
  56  * @param chip          create the table for a specific chip, -1 read all chips.
  57  *              Applies only if NAND_BBT_PERCHIP option is set
  58  *
  59  * Create a bad block table by scanning the device
  60  * for the given good/bad block identify pattern
  61  */
  62 static int create_bbt(struct mtd_info *mtd, uint8_t * buf,
  63                       struct nand_bbt_descr *bd, int chip)
  64 {
  65         struct onenand_chip *this = mtd->priv;
  66         struct bbm_info *bbm = this->bbm;
  67         int i, j, numblocks, len, scanlen;
  68         int startblock;
  69         loff_t from;
  70         size_t readlen, ooblen;
  71         struct mtd_oob_ops ops;
  72         int rgn;
  73
  74         printk(KERN_INFO "Scanning device for bad blocks\n");
  75
  76         len = 1;
  77
  78         /* We need only read few bytes from the OOB area */
  79         scanlen = ooblen = 0;
  80         readlen = bd->len;
  81
  82         /* chip == -1 case only */
  83         /* Note that numblocks is 2 * (real numblocks) here;
  84          * see i += 2 below as it makses shifting and masking less painful
  85          */
  86         numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
  87         startblock = 0;
  88         from = 0;
  89
  90         ops.mode = MTD_OPS_PLACE_OOB;
  91         ops.ooblen = readlen;
  92         ops.oobbuf = buf;
  93         ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
  94
  95         for (i = startblock; i < numblocks;) {
  96                 int ret;
  97
  98                 for (j = 0; j < len; j++) {
  99                         /* No need to read pages fully,
 100                          * just read required OOB bytes */
 101                         ret = onenand_bbt_read_oob(mtd,
 102                                              from + j * mtd->writesize +
 103                                              bd->offs, &ops);
 104
 105                         /* If it is a initial bad block, just ignore it */
 106                         if (ret == ONENAND_BBT_READ_FATAL_ERROR)
 107                                 return -EIO;
 108
 109                         if (ret || check_short_pattern
 110                             (&buf[j * scanlen], scanlen, mtd->writesize, bd)) {
 111                                 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
 112                                 printk(KERN_WARNING
 113                                        "Bad eraseblock %d at 0x%08x\n", i >> 1,
 114                                        (unsigned int)from);
 115                                 break;
 116                         }
 117                 }
 118                 i += 2;
 119
 120                 if (FLEXONENAND(this)) {
 121                         rgn = flexonenand_region(mtd, from);
 122                         from += mtd->eraseregions[rgn].erasesize;
 123                 } else
 124                         from += (1 << bbm->bbt_erase_shift);
 125         }
 126
 127         return 0;
 128 }
 129
 130 /**
 131  * onenand_memory_bbt - [GENERIC] create a memory based bad block table
 132  * @param mtd           MTD device structure
 133  * @param bd            descriptor for the good/bad block search pattern
 134  *
 135  * The function creates a memory based bbt by scanning the device
 136  * for manufacturer / software marked good / bad blocks
 137  */
 138 static inline int onenand_memory_bbt(struct mtd_info *mtd,
 139                                      struct nand_bbt_descr *bd)
 140 {
 141         unsigned char data_buf[MAX_ONENAND_PAGESIZE];
 142
 143         return create_bbt(mtd, data_buf, bd, -1);
 144 }
 145
 146 /**
 147  * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
 148  * @param mtd           MTD device structure
 149  * @param offs          offset in the device
 150  * @param allowbbt      allow access to bad block table region
 151  */
 152 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
 153 {
 154         struct onenand_chip *this = mtd->priv;
 155         struct bbm_info *bbm = this->bbm;
 156         int block;
 157         uint8_t res;
 158
 159         /* Get block number * 2 */
 160         block = (int) (onenand_block(this, offs) << 1);
 161         res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
 162
 163         pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
 164                  (unsigned int)offs, block >> 1, res);
 165
 166         switch ((int)res) {
 167         case 0x00:
 168                 return 0;
 169         case 0x01:
 170                 return 1;
 171         case 0x02:
 172                 return allowbbt ? 0 : 1;
 173         }
 174
 175         return 1;
 176 }
 177
 178 /**
 179  * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
 180  * @param mtd           MTD device structure
 181  * @param bd            descriptor for the good/bad block search pattern
 182  *
 183  * The function checks, if a bad block table(s) is/are already
 184  * available. If not it scans the device for manufacturer
 185  * marked good / bad blocks and writes the bad block table(s) to
 186  * the selected place.
 187  *
 188  * The bad block table memory is allocated here. It must be freed
 189  * by calling the onenand_free_bbt function.
 190  *
 191  */
 192 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 193 {
 194         struct onenand_chip *this = mtd->priv;
 195         struct bbm_info *bbm = this->bbm;
 196         int len, ret = 0;
 197
 198         len = this->chipsize >> (this->erase_shift + 2);
 199         /* Allocate memory (2bit per block) */
 200         bbm->bbt = malloc(len);
 201         if (!bbm->bbt)
 202                 return -ENOMEM;
 203         /* Clear the memory bad block table */
 204         memset(bbm->bbt, 0x00, len);
 205
 206         /* Set the bad block position */
 207         bbm->badblockpos = ONENAND_BADBLOCK_POS;
 208
 209         /* Set erase shift */
 210         bbm->bbt_erase_shift = this->erase_shift;
 211
 212         if (!bbm->isbad_bbt)
 213                 bbm->isbad_bbt = onenand_isbad_bbt;
 214
 215         /* Scan the device to build a memory based bad block table */
 216         if ((ret = onenand_memory_bbt(mtd, bd))) {
 217                 printk(KERN_ERR
 218                        "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
 219                 free(bbm->bbt);
 220                 bbm->bbt = NULL;
 221         }
 222
 223         return ret;
 224 }
 225
 226 /*
 227  * Define some generic bad / good block scan pattern which are used
 228  * while scanning a device for factory marked good / bad blocks.
 229  */
 230 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
 231
 232 static struct nand_bbt_descr largepage_memorybased = {
 233         .options = 0,
 234         .offs = 0,
 235         .len = 2,
 236         .pattern = scan_ff_pattern,
 237 };
 238
 239 /**
 240  * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
 241  * @param mtd           MTD device structure
 242  *
 243  * This function selects the default bad block table
 244  * support for the device and calls the onenand_scan_bbt function
 245  */
 246 int onenand_default_bbt(struct mtd_info *mtd)
 247 {
 248         struct onenand_chip *this = mtd->priv;
 249         struct bbm_info *bbm;
 250
 251         this->bbm = malloc(sizeof(struct bbm_info));
 252         if (!this->bbm)
 253                 return -ENOMEM;
 254
 255         bbm = this->bbm;
 256
 257         memset(bbm, 0, sizeof(struct bbm_info));
 258
 259         /* 1KB page has same configuration as 2KB page */
 260         if (!bbm->badblock_pattern)
 261                 bbm->badblock_pattern = &largepage_memorybased;
 262
 263         return onenand_scan_bbt(mtd, bbm->badblock_pattern);
 264 }