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) 2005-2007 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
  72         printk(KERN_INFO "Scanning device for bad blocks\n");
  73
  74         len = 1;
  75
  76         /* We need only read few bytes from the OOB area */
  77         scanlen = ooblen = 0;
  78         readlen = bd->len;
  79
  80         /* chip == -1 case only */
  81         /* Note that numblocks is 2 * (real numblocks) here;
  82          * see i += 2 below as it makses shifting and masking less painful
  83          */
  84         numblocks = mtd->size >> (bbm->bbt_erase_shift - 1);
  85         startblock = 0;
  86         from = 0;
  87
  88         for (i = startblock; i < numblocks;) {
  89                 int ret;
  90
  91                 for (j = 0; j < len; j++) {
  92                         size_t retlen;
  93
  94                         /* No need to read pages fully,
  95                          * just read required OOB bytes */
  96                         ret = onenand_read_oob(mtd,
  97                                              from + j * mtd->writesize +
  98                                              bd->offs, readlen, &retlen,
  99                                              &buf[0]);
 100
 101                         if (ret && ret != -EAGAIN) {
 102                                 printk("ret = %d\n", ret);
 103                                 return ret;
 104                         }
 105
 106                         if (check_short_pattern
 107                             (&buf[j * scanlen], scanlen, mtd->writesize, bd)) {
 108                                 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
 109                                 printk(KERN_WARNING
 110                                        "Bad eraseblock %d at 0x%08x\n", i >> 1,
 111                                        (unsigned int)from);
 112                                 break;
 113                         }
 114                 }
 115                 i += 2;
 116                 from += (1 << bbm->bbt_erase_shift);
 117         }
 118
 119         return 0;
 120 }
 121
 122 /**
 123  * onenand_memory_bbt - [GENERIC] create a memory based bad block table
 124  * @param mtd           MTD device structure
 125  * @param bd            descriptor for the good/bad block search pattern
 126  *
 127  * The function creates a memory based bbt by scanning the device
 128  * for manufacturer / software marked good / bad blocks
 129  */
 130 static inline int onenand_memory_bbt(struct mtd_info *mtd,
 131                                      struct nand_bbt_descr *bd)
 132 {
 133         unsigned char data_buf[MAX_ONENAND_PAGESIZE];
 134
 135         bd->options &= ~NAND_BBT_SCANEMPTY;
 136         return create_bbt(mtd, data_buf, bd, -1);
 137 }
 138
 139 /**
 140  * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
 141  * @param mtd           MTD device structure
 142  * @param offs          offset in the device
 143  * @param allowbbt      allow access to bad block table region
 144  */
 145 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
 146 {
 147         struct onenand_chip *this = mtd->priv;
 148         struct bbm_info *bbm = this->bbm;
 149         int block;
 150         uint8_t res;
 151
 152         /* Get block number * 2 */
 153         block = (int)(offs >> (bbm->bbt_erase_shift - 1));
 154         res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
 155
 156         MTDDEBUG (MTD_DEBUG_LEVEL2,
 157                   "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
 158                   (unsigned int)offs, block >> 1, res);
 159
 160         switch ((int)res) {
 161         case 0x00:
 162                 return 0;
 163         case 0x01:
 164                 return 1;
 165         case 0x02:
 166                 return allowbbt ? 0 : 1;
 167         }
 168
 169         return 1;
 170 }
 171
 172 /**
 173  * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
 174  * @param mtd           MTD device structure
 175  * @param bd            descriptor for the good/bad block search pattern
 176  *
 177  * The function checks, if a bad block table(s) is/are already
 178  * available. If not it scans the device for manufacturer
 179  * marked good / bad blocks and writes the bad block table(s) to
 180  * the selected place.
 181  *
 182  * The bad block table memory is allocated here. It must be freed
 183  * by calling the onenand_free_bbt function.
 184  *
 185  */
 186 int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 187 {
 188         struct onenand_chip *this = mtd->priv;
 189         struct bbm_info *bbm = this->bbm;
 190         int len, ret = 0;
 191
 192         len = mtd->size >> (this->erase_shift + 2);
 193         /* Allocate memory (2bit per block) */
 194         bbm->bbt = malloc(len);
 195         if (!bbm->bbt) {
 196                 printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");
 197                 return -ENOMEM;
 198         }
 199         /* Clear the memory bad block table */
 200         memset(bbm->bbt, 0x00, len);
 201
 202         /* Set the bad block position */
 203         bbm->badblockpos = ONENAND_BADBLOCK_POS;
 204
 205         /* Set erase shift */
 206         bbm->bbt_erase_shift = this->erase_shift;
 207
 208         if (!bbm->isbad_bbt)
 209                 bbm->isbad_bbt = onenand_isbad_bbt;
 210
 211         /* Scan the device to build a memory based bad block table */
 212         if ((ret = onenand_memory_bbt(mtd, bd))) {
 213                 printk(KERN_ERR
 214                        "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
 215                 free(bbm->bbt);
 216                 bbm->bbt = NULL;
 217         }
 218
 219         return ret;
 220 }
 221
 222 /*
 223  * Define some generic bad / good block scan pattern which are used
 224  * while scanning a device for factory marked good / bad blocks.
 225  */
 226 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
 227
 228 static struct nand_bbt_descr largepage_memorybased = {
 229         .options = 0,
 230         .offs = 0,
 231         .len = 2,
 232         .pattern = scan_ff_pattern,
 233 };
 234
 235 /**
 236  * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
 237  * @param mtd           MTD device structure
 238  *
 239  * This function selects the default bad block table
 240  * support for the device and calls the onenand_scan_bbt function
 241  */
 242 int onenand_default_bbt(struct mtd_info *mtd)
 243 {
 244         struct onenand_chip *this = mtd->priv;
 245         struct bbm_info *bbm;
 246
 247         this->bbm = malloc(sizeof(struct bbm_info));
 248         if (!this->bbm)
 249                 return -ENOMEM;
 250
 251         bbm = this->bbm;
 252
 253         memset(bbm, 0, sizeof(struct bbm_info));
 254
 255         /* 1KB page has same configuration as 2KB page */
 256         if (!bbm->badblock_pattern)
 257                 bbm->badblock_pattern = &largepage_memorybased;
 258
 259         return onenand_scan_bbt(mtd, bbm->badblock_pattern);
 260 }