drivers/mtd/nand/onenand/onenand_bbt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Bad Block Table support for the OneNAND driver
   4  *
   5  *  Copyright(c) 2005 Samsung Electronics
   6  *  Kyungmin Park <kyungmin.park@samsung.com>
   7  *
   8  *  Derived from nand_bbt.c
   9  *
  10  *  TODO:
  11  *    Split BBT core and chip specific BBT.
  12  */
  13
  14 #include <linux/slab.h>
  15 #include <linux/mtd/mtd.h>
  16 #include <linux/mtd/onenand.h>
  17 #include <linux/export.h>
  18
  19 /**
  20  * check_short_pattern - [GENERIC] check if a pattern is in the buffer
  21  * @param buf           the buffer to search
  22  * @param len           the length of buffer to search
  23  * @param paglen        the pagelength
  24  * @param td            search pattern descriptor
  25  *
  26  * Check for a pattern at the given place. Used to search bad block
  27  * tables and good / bad block identifiers. Same as check_pattern, but
  28  * no optional empty check and the pattern is expected to start
  29  * at offset 0.
  30  *
  31  */
  32 static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
  33 {
  34         int i;
  35         uint8_t *p = buf;
  36
  37         /* Compare the pattern */
  38         for (i = 0; i < td->len; i++) {
  39                 if (p[i] != td->pattern[i])
  40                         return -1;
  41         }
  42         return 0;
  43 }
  44
  45 /**
  46  * create_bbt - [GENERIC] Create a bad block table by scanning the device
  47  * @param mtd           MTD device structure
  48  * @param buf           temporary buffer
  49  * @param bd            descriptor for the good/bad block search pattern
  50  * @param chip          create the table for a specific chip, -1 read all chips.
  51  *              Applies only if NAND_BBT_PERCHIP option is set
  52  *
  53  * Create a bad block table by scanning the device
  54  * for the given good/bad block identify pattern
  55  */
  56 static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
  57 {
  58         struct onenand_chip *this = mtd->priv;
  59         struct bbm_info *bbm = this->bbm;
  60         int i, j, numblocks, len, scanlen;
  61         int startblock;
  62         loff_t from;
  63         size_t readlen, ooblen;
  64         struct mtd_oob_ops ops;
  65         int rgn;
  66
  67         printk(KERN_INFO "Scanning device for bad blocks\n");
  68
  69         len = 2;
  70
  71         /* We need only read few bytes from the OOB area */
  72         scanlen = ooblen = 0;
  73         readlen = bd->len;
  74
  75         /* chip == -1 case only */
  76         /* Note that numblocks is 2 * (real numblocks) here;
  77          * see i += 2 below as it makses shifting and masking less painful
  78          */
  79         numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
  80         startblock = 0;
  81         from = 0;
  82
  83         ops.mode = MTD_OPS_PLACE_OOB;
  84         ops.ooblen = readlen;
  85         ops.oobbuf = buf;
  86         ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
  87
  88         for (i = startblock; i < numblocks; ) {
  89                 int ret;
  90
  91                 for (j = 0; j < len; j++) {
  92                         /* No need to read pages fully,
  93                          * just read required OOB bytes */
  94                         ret = onenand_bbt_read_oob(mtd,
  95                                 from + j * this->writesize + bd->offs, &ops);
  96
  97                         /* If it is a initial bad block, just ignore it */
  98                         if (ret == ONENAND_BBT_READ_FATAL_ERROR)
  99                                 return -EIO;
 100
 101                         if (ret || check_short_pattern(&buf[j * scanlen],
 102                                                scanlen, this->writesize, bd)) {
 103                                 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
 104                                 printk(KERN_INFO "OneNAND eraseblock %d is an "
 105                                         "initial bad block\n", i >> 1);
 106                                 mtd->ecc_stats.badblocks++;
 107                                 break;
 108                         }
 109                 }
 110                 i += 2;
 111
 112                 if (FLEXONENAND(this)) {
 113                         rgn = flexonenand_region(mtd, from);
 114                         from += mtd->eraseregions[rgn].erasesize;
 115                 } else
 116                         from += (1 << bbm->bbt_erase_shift);
 117         }
 118
 119         return 0;
 120 }
 121
 122
 123 /**
 124  * onenand_memory_bbt - [GENERIC] create a memory based bad block table
 125  * @param mtd           MTD device structure
 126  * @param bd            descriptor for the good/bad block search pattern
 127  *
 128  * The function creates a memory based bbt by scanning the device
 129  * for manufacturer / software marked good / bad blocks
 130  */
 131 static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
 132 {
 133         struct onenand_chip *this = mtd->priv;
 134
 135         return create_bbt(mtd, this->page_buf, bd, -1);
 136 }
 137
 138 /**
 139  * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
 140  * @param mtd           MTD device structure
 141  * @param offs          offset in the device
 142  * @param allowbbt      allow access to bad block table region
 143  */
 144 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
 145 {
 146         struct onenand_chip *this = mtd->priv;
 147         struct bbm_info *bbm = this->bbm;
 148         int block;
 149         uint8_t res;
 150
 151         /* Get block number * 2 */
 152         block = (int) (onenand_block(this, offs) << 1);
 153         res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
 154
 155         pr_debug("onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
 156                 (unsigned int) offs, block >> 1, res);
 157
 158         switch ((int) res) {
 159         case 0x00:      return 0;
 160         case 0x01:      return 1;
 161         case 0x02:      return allowbbt ? 0 : 1;
 162         }
 163
 164         return 1;
 165 }
 166
 167 /**
 168  * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
 169  * @param mtd           MTD device structure
 170  * @param bd            descriptor for the good/bad block search pattern
 171  *
 172  * The function checks, if a bad block table(s) is/are already
 173  * available. If not it scans the device for manufacturer
 174  * marked good / bad blocks and writes the bad block table(s) to
 175  * the selected place.
 176  *
 177  * The bad block table memory is allocated here. It is freed
 178  * by the onenand_release function.
 179  *
 180  */
 181 static int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 182 {
 183         struct onenand_chip *this = mtd->priv;
 184         struct bbm_info *bbm = this->bbm;
 185         int len, ret = 0;
 186
 187         len = this->chipsize >> (this->erase_shift + 2);
 188         /* Allocate memory (2bit per block) and clear the memory bad block table */
 189         bbm->bbt = kzalloc(len, GFP_KERNEL);
 190         if (!bbm->bbt)
 191                 return -ENOMEM;
 192
 193         /* Set erase shift */
 194         bbm->bbt_erase_shift = this->erase_shift;
 195
 196         if (!bbm->isbad_bbt)
 197                 bbm->isbad_bbt = onenand_isbad_bbt;
 198
 199         /* Scan the device to build a memory based bad block table */
 200         if ((ret = onenand_memory_bbt(mtd, bd))) {
 201                 printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
 202                 kfree(bbm->bbt);
 203                 bbm->bbt = NULL;
 204         }
 205
 206         return ret;
 207 }
 208
 209 /*
 210  * Define some generic bad / good block scan pattern which are used
 211  * while scanning a device for factory marked good / bad blocks.
 212  */
 213 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
 214
 215 static struct nand_bbt_descr largepage_memorybased = {
 216         .options = 0,
 217         .offs = 0,
 218         .len = 2,
 219         .pattern = scan_ff_pattern,
 220 };
 221
 222 /**
 223  * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
 224  * @param mtd           MTD device structure
 225  *
 226  * This function selects the default bad block table
 227  * support for the device and calls the onenand_scan_bbt function
 228  */
 229 int onenand_default_bbt(struct mtd_info *mtd)
 230 {
 231         struct onenand_chip *this = mtd->priv;
 232         struct bbm_info *bbm;
 233
 234         this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL);
 235         if (!this->bbm)
 236                 return -ENOMEM;
 237
 238         bbm = this->bbm;
 239
 240         /* 1KB page has same configuration as 2KB page */
 241         if (!bbm->badblock_pattern)
 242                 bbm->badblock_pattern = &largepage_memorybased;
 243
 244         return onenand_scan_bbt(mtd, bbm->badblock_pattern);
 245 }