drivers/mtd/onenand/onenand_bbt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/drivers/mtd/onenand/onenand_bbt.c
   4  *
   5  *  Bad Block Table support for the OneNAND driver
   6  *
   7  *  Copyright(c) 2005 Samsung Electronics
   8  *  Kyungmin Park <kyungmin.park@samsung.com>
   9  *
  10  *  Derived from nand_bbt.c
  11  *
  12  *  TODO:
  13  *    Split BBT core and chip specific BBT.
  14  */
  15
  16 #include <linux/slab.h>
  17 #include <linux/mtd/mtd.h>
  18 #include <linux/mtd/onenand.h>
  19 #include <linux/export.h>
  20
  21 /**
  22  * check_short_pattern - [GENERIC] check if a pattern is in the buffer
  23  * @param buf           the buffer to search
  24  * @param len           the length of buffer to search
  25  * @param paglen        the pagelength
  26  * @param td            search pattern descriptor
  27  *
  28  * Check for a pattern at the given place. Used to search bad block
  29  * tables and good / bad block identifiers. Same as check_pattern, but
  30  * no optional empty check and the pattern is expected to start
  31  * at offset 0.
  32  *
  33  */
  34 static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
  35 {
  36         int i;
  37         uint8_t *p = buf;
  38
  39         /* Compare the pattern */
  40         for (i = 0; i < td->len; i++) {
  41                 if (p[i] != td->pattern[i])
  42                         return -1;
  43         }
  44         return 0;
  45 }
  46
  47 /**
  48  * create_bbt - [GENERIC] Create a bad block table by scanning the device
  49  * @param mtd           MTD device structure
  50  * @param buf           temporary buffer
  51  * @param bd            descriptor for the good/bad block search pattern
  52  * @param chip          create the table for a specific chip, -1 read all chips.
  53  *              Applies only if NAND_BBT_PERCHIP option is set
  54  *
  55  * Create a bad block table by scanning the device
  56  * for the given good/bad block identify pattern
  57  */
  58 static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
  59 {
  60         struct onenand_chip *this = mtd->priv;
  61         struct bbm_info *bbm = this->bbm;
  62         int i, j, numblocks, len, scanlen;
  63         int startblock;
  64         loff_t from;
  65         size_t readlen, ooblen;
  66         struct mtd_oob_ops ops;
  67         int rgn;
  68
  69         printk(KERN_INFO "Scanning device for bad blocks\n");
  70
  71         len = 2;
  72
  73         /* We need only read few bytes from the OOB area */
  74         scanlen = ooblen = 0;
  75         readlen = bd->len;
  76
  77         /* chip == -1 case only */
  78         /* Note that numblocks is 2 * (real numblocks) here;
  79          * see i += 2 below as it makses shifting and masking less painful
  80          */
  81         numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
  82         startblock = 0;
  83         from = 0;
  84
  85         ops.mode = MTD_OPS_PLACE_OOB;
  86         ops.ooblen = readlen;
  87         ops.oobbuf = buf;
  88         ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
  89
  90         for (i = startblock; i < numblocks; ) {
  91                 int ret;
  92
  93                 for (j = 0; j < len; j++) {
  94                         /* No need to read pages fully,
  95                          * just read required OOB bytes */
  96                         ret = onenand_bbt_read_oob(mtd,
  97                                 from + j * this->writesize + bd->offs, &ops);
  98
  99                         /* If it is a initial bad block, just ignore it */
 100                         if (ret == ONENAND_BBT_READ_FATAL_ERROR)
 101                                 return -EIO;
 102
 103                         if (ret || check_short_pattern(&buf[j * scanlen],
 104                                                scanlen, this->writesize, bd)) {
 105                                 bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
 106                                 printk(KERN_INFO "OneNAND eraseblock %d is an "
 107                                         "initial bad block\n", i >> 1);
 108                                 mtd->ecc_stats.badblocks++;
 109                                 break;
 110                         }
 111                 }
 112                 i += 2;
 113
 114                 if (FLEXONENAND(this)) {
 115                         rgn = flexonenand_region(mtd, from);
 116                         from += mtd->eraseregions[rgn].erasesize;
 117                 } else
 118                         from += (1 << bbm->bbt_erase_shift);
 119         }
 120
 121         return 0;
 122 }
 123
 124
 125 /**
 126  * onenand_memory_bbt - [GENERIC] create a memory based bad block table
 127  * @param mtd           MTD device structure
 128  * @param bd            descriptor for the good/bad block search pattern
 129  *
 130  * The function creates a memory based bbt by scanning the device
 131  * for manufacturer / software marked good / bad blocks
 132  */
 133 static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
 134 {
 135         struct onenand_chip *this = mtd->priv;
 136
 137         return create_bbt(mtd, this->page_buf, bd, -1);
 138 }
 139
 140 /**
 141  * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
 142  * @param mtd           MTD device structure
 143  * @param offs          offset in the device
 144  * @param allowbbt      allow access to bad block table region
 145  */
 146 static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
 147 {
 148         struct onenand_chip *this = mtd->priv;
 149         struct bbm_info *bbm = this->bbm;
 150         int block;
 151         uint8_t res;
 152
 153         /* Get block number * 2 */
 154         block = (int) (onenand_block(this, offs) << 1);
 155         res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
 156
 157         pr_debug("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:      return 0;
 162         case 0x01:      return 1;
 163         case 0x02:      return allowbbt ? 0 : 1;
 164         }
 165
 166         return 1;
 167 }
 168
 169 /**
 170  * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
 171  * @param mtd           MTD device structure
 172  * @param bd            descriptor for the good/bad block search pattern
 173  *
 174  * The function checks, if a bad block table(s) is/are already
 175  * available. If not it scans the device for manufacturer
 176  * marked good / bad blocks and writes the bad block table(s) to
 177  * the selected place.
 178  *
 179  * The bad block table memory is allocated here. It is freed
 180  * by the onenand_release function.
 181  *
 182  */
 183 static int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
 184 {
 185         struct onenand_chip *this = mtd->priv;
 186         struct bbm_info *bbm = this->bbm;
 187         int len, ret = 0;
 188
 189         len = this->chipsize >> (this->erase_shift + 2);
 190         /* Allocate memory (2bit per block) and clear the memory bad block table */
 191         bbm->bbt = kzalloc(len, GFP_KERNEL);
 192         if (!bbm->bbt)
 193                 return -ENOMEM;
 194
 195         /* Set the bad block position */
 196         bbm->badblockpos = ONENAND_BADBLOCK_POS;
 197
 198         /* Set erase shift */
 199         bbm->bbt_erase_shift = this->erase_shift;
 200
 201         if (!bbm->isbad_bbt)
 202                 bbm->isbad_bbt = onenand_isbad_bbt;
 203
 204         /* Scan the device to build a memory based bad block table */
 205         if ((ret = onenand_memory_bbt(mtd, bd))) {
 206                 printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
 207                 kfree(bbm->bbt);
 208                 bbm->bbt = NULL;
 209         }
 210
 211         return ret;
 212 }
 213
 214 /*
 215  * Define some generic bad / good block scan pattern which are used
 216  * while scanning a device for factory marked good / bad blocks.
 217  */
 218 static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
 219
 220 static struct nand_bbt_descr largepage_memorybased = {
 221         .options = 0,
 222         .offs = 0,
 223         .len = 2,
 224         .pattern = scan_ff_pattern,
 225 };
 226
 227 /**
 228  * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
 229  * @param mtd           MTD device structure
 230  *
 231  * This function selects the default bad block table
 232  * support for the device and calls the onenand_scan_bbt function
 233  */
 234 int onenand_default_bbt(struct mtd_info *mtd)
 235 {
 236         struct onenand_chip *this = mtd->priv;
 237         struct bbm_info *bbm;
 238
 239         this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL);
 240         if (!this->bbm)
 241                 return -ENOMEM;
 242
 243         bbm = this->bbm;
 244
 245         /* 1KB page has same configuration as 2KB page */
 246         if (!bbm->badblock_pattern)
 247                 bbm->badblock_pattern = &largepage_memorybased;
 248
 249         return onenand_scan_bbt(mtd, bbm->badblock_pattern);
 250 }