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/mtd/compat.h>
  19 #include <linux/mtd/mtd.h>
  20 #include <linux/mtd/onenand.h>
  21 #include <malloc.h>
  22
  23 #include <asm/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
  73         printk(KERN_INFO "Scanning device for bad blocks\n");
  74
  75         len = 1;
  76
  77         /* We need only read few bytes from the OOB area */
  78         scanlen = ooblen = 0;
  79         readlen = bd->len;
  80
  81         /* chip == -1 case only */
  82         /* Note that numblocks is 2 * (real numblocks) here;
  83          * see i += 2 below as it makses shifting and masking less painful
  84          */
  85         numblocks = mtd->size >> (bbm->bbt_erase_shift - 1);
  86         startblock = 0;
  87         from = 0;
  88
  89         ops.mode = MTD_OOB_PLACE;
  90         ops.ooblen = readlen;
  91         ops.oobbuf = buf;
  92         ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
  93
  94         for (i = startblock; i < numblocks;) {
  95                 int ret;
  96
  97                 for (j = 0; j < len; j++) {
  98                         /* No need to read pages fully,
  99                          * just read required OOB bytes */
 100                         ret = onenand_bbt_read_oob(mtd,
 101                                              from + j * mtd->writesize +
 102                                              bd->offs, &ops);
 103
 104                         /* If it is a initial bad block, just ignore it */
 105                         if (ret == ONENAND_BBT_READ_FATAL_ERROR)
 106                                 return -EIO;
 107
 108                         if (ret || check_short_pattern
 109                             (&buf[j * scanlen], scanlen, mtd->writesize, bd)) {
 110                                 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
 111                                 printk(KERN_WARNING
 112                                        "Bad eraseblock %d at 0x%08x\n", i >> 1,
 113                                        (unsigned int)from);
 114                                 break;
 115                         }
 116                 }
 117                 i += 2;
 118                 from += (1 << bbm->bbt_erase_shift);
 119         }
 120
 121         return 0;
 122 }
 123
 124 /**
 125  * onenand_memory_bbt - [GENERIC] create a memory based bad block table
 126  * @param mtd           MTD device structure
 127  * @param bd            descriptor for the good/bad block search pattern
 128  *
 129  * The function creates a memory based bbt by scanning the device
 130  * for manufacturer / software marked good / bad blocks
 131  */
 132 static inline int onenand_memory_bbt(struct mtd_info *mtd,
 133                                      struct nand_bbt_descr *bd)
 134 {
 135         unsigned char data_buf[MAX_ONENAND_PAGESIZE];
 136
 137         bd->options &= ~NAND_BBT_SCANEMPTY;
 138         return create_bbt(mtd, data_buf, bd, -1);
 139 }
 140
 141 /**
 142  * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
 143  * @param mtd           MTD device structure
 144  * @param offs          offset in the device
 145  * @param allowbbt      allow access to bad block table region
 146  */
 147 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
 148 {
 149         struct onenand_chip *this = mtd->priv;
 150         struct bbm_info *bbm = this->bbm;
 151         int block;
 152         uint8_t res;
 153
 154         /* Get block number * 2 */
 155         block = (int)(offs >> (bbm->bbt_erase_shift - 1));
 156         res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
 157
 158         MTDDEBUG (MTD_DEBUG_LEVEL2,
 159                 "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
 160                 (unsigned int)offs, block >> 1, res);
 161
 162         switch ((int)res) {
 163         case 0x00:
 164                 return 0;
 165         case 0x01:
 166                 return 1;
 167         case 0x02:
 168                 return allowbbt ? 0 : 1;
 169         }
 170
 171         return 1;
 172 }
 173
 174 /**
 175  * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
 176  * @param mtd           MTD device structure
 177  * @param bd            descriptor for the good/bad block search pattern
 178  *
 179  * The function checks, if a bad block table(s) is/are already
 180  * available. If not it scans the device for manufacturer
 181  * marked good / bad blocks and writes the bad block table(s) to
 182  * the selected place.
 183  *
 184  * The bad block table memory is allocated here. It must be freed
 185  * by calling the onenand_free_bbt function.
 186  *
 187  */
 188 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 189 {
 190         struct onenand_chip *this = mtd->priv;
 191         struct bbm_info *bbm = this->bbm;
 192         int len, ret = 0;
 193
 194         len = mtd->size >> (this->erase_shift + 2);
 195         /* Allocate memory (2bit per block) */
 196         bbm->bbt = malloc(len);
 197         if (!bbm->bbt) {
 198                 printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");
 199                 return -ENOMEM;
 200         }
 201         /* Clear the memory bad block table */
 202         memset(bbm->bbt, 0x00, len);
 203
 204         /* Set the bad block position */
 205         bbm->badblockpos = ONENAND_BADBLOCK_POS;
 206
 207         /* Set erase shift */
 208         bbm->bbt_erase_shift = this->erase_shift;
 209
 210         if (!bbm->isbad_bbt)
 211                 bbm->isbad_bbt = onenand_isbad_bbt;
 212
 213         /* Scan the device to build a memory based bad block table */
 214         if ((ret = onenand_memory_bbt(mtd, bd))) {
 215                 printk(KERN_ERR
 216                        "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
 217                 free(bbm->bbt);
 218                 bbm->bbt = NULL;
 219         }
 220
 221         return ret;
 222 }
 223
 224 /*
 225  * Define some generic bad / good block scan pattern which are used
 226  * while scanning a device for factory marked good / bad blocks.
 227  */
 228 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
 229
 230 static struct nand_bbt_descr largepage_memorybased = {
 231         .options = 0,
 232         .offs = 0,
 233         .len = 2,
 234         .pattern = scan_ff_pattern,
 235 };
 236
 237 /**
 238  * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
 239  * @param mtd           MTD device structure
 240  *
 241  * This function selects the default bad block table
 242  * support for the device and calls the onenand_scan_bbt function
 243  */
 244 int onenand_default_bbt(struct mtd_info *mtd)
 245 {
 246         struct onenand_chip *this = mtd->priv;
 247         struct bbm_info *bbm;
 248
 249         this->bbm = malloc(sizeof(struct bbm_info));
 250         if (!this->bbm)
 251                 return -ENOMEM;
 252
 253         bbm = this->bbm;
 254
 255         memset(bbm, 0, sizeof(struct bbm_info));
 256
 257         /* 1KB page has same configuration as 2KB page */
 258         if (!bbm->badblock_pattern)
 259                 bbm->badblock_pattern = &largepage_memorybased;
 260
 261         return onenand_scan_bbt(mtd, bbm->badblock_pattern);
 262 }