255 lines
6.8 KiB
C
255 lines
6.8 KiB
C
/*
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* linux/drivers/mtd/onenand/onenand_bbt.c
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*
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* Bad Block Table support for the OneNAND driver
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*
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* Copyright(c) 2005 Samsung Electronics
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* Kyungmin Park <kyungmin.park@samsung.com>
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*
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* Derived from nand_bbt.c
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*
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* TODO:
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* Split BBT core and chip specific BBT.
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*/
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#include <linux/slab.h>
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#include <linux/mtd/mtd.h>
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#include <linux/mtd/onenand.h>
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/**
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* check_short_pattern - [GENERIC] check if a pattern is in the buffer
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* @param buf the buffer to search
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* @param len the length of buffer to search
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* @param paglen the pagelength
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* @param td search pattern descriptor
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*
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* Check for a pattern at the given place. Used to search bad block
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* tables and good / bad block identifiers. Same as check_pattern, but
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* no optional empty check and the pattern is expected to start
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* at offset 0.
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*
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*/
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static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)
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{
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int i;
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uint8_t *p = buf;
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/* Compare the pattern */
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for (i = 0; i < td->len; i++) {
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if (p[i] != td->pattern[i])
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return -1;
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}
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return 0;
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}
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/**
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* create_bbt - [GENERIC] Create a bad block table by scanning the device
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* @param mtd MTD device structure
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* @param buf temporary buffer
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* @param bd descriptor for the good/bad block search pattern
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* @param chip create the table for a specific chip, -1 read all chips.
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* Applies only if NAND_BBT_PERCHIP option is set
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*
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* Create a bad block table by scanning the device
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* for the given good/bad block identify pattern
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*/
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static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)
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{
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struct onenand_chip *this = mtd->priv;
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struct bbm_info *bbm = this->bbm;
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int i, j, numblocks, len, scanlen;
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int startblock;
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loff_t from;
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size_t readlen, ooblen;
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struct mtd_oob_ops ops;
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int rgn;
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printk(KERN_INFO "Scanning device for bad blocks\n");
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len = 2;
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/* We need only read few bytes from the OOB area */
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scanlen = ooblen = 0;
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readlen = bd->len;
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/* chip == -1 case only */
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/* Note that numblocks is 2 * (real numblocks) here;
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* see i += 2 below as it makses shifting and masking less painful
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*/
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numblocks = this->chipsize >> (bbm->bbt_erase_shift - 1);
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startblock = 0;
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from = 0;
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ops.mode = MTD_OOB_PLACE;
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ops.ooblen = readlen;
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ops.oobbuf = buf;
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ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
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for (i = startblock; i < numblocks; ) {
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int ret;
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for (j = 0; j < len; j++) {
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/* No need to read pages fully,
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* just read required OOB bytes */
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ret = onenand_bbt_read_oob(mtd,
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from + j * this->writesize + bd->offs, &ops);
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/* If it is a initial bad block, just ignore it */
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if (ret == ONENAND_BBT_READ_FATAL_ERROR)
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return -EIO;
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if (ret || check_short_pattern(&buf[j * scanlen],
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scanlen, this->writesize, bd)) {
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bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);
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printk(KERN_INFO "OneNAND eraseblock %d is an "
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"initial bad block\n", i >> 1);
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mtd->ecc_stats.badblocks++;
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break;
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}
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}
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i += 2;
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if (FLEXONENAND(this)) {
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rgn = flexonenand_region(mtd, from);
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from += mtd->eraseregions[rgn].erasesize;
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} else
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from += (1 << bbm->bbt_erase_shift);
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}
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return 0;
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}
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/**
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* onenand_memory_bbt - [GENERIC] create a memory based bad block table
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* @param mtd MTD device structure
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* @param bd descriptor for the good/bad block search pattern
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*
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* The function creates a memory based bbt by scanning the device
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* for manufacturer / software marked good / bad blocks
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*/
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static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)
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{
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struct onenand_chip *this = mtd->priv;
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bd->options &= ~NAND_BBT_SCANEMPTY;
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return create_bbt(mtd, this->page_buf, bd, -1);
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}
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/**
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* onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad
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* @param mtd MTD device structure
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* @param offs offset in the device
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* @param allowbbt allow access to bad block table region
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*/
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static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)
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{
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struct onenand_chip *this = mtd->priv;
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struct bbm_info *bbm = this->bbm;
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int block;
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uint8_t res;
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/* Get block number * 2 */
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block = (int) (onenand_block(this, offs) << 1);
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res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;
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DEBUG(MTD_DEBUG_LEVEL2, "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",
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(unsigned int) offs, block >> 1, res);
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switch ((int) res) {
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case 0x00: return 0;
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case 0x01: return 1;
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case 0x02: return allowbbt ? 0 : 1;
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}
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return 1;
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}
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/**
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* onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)
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* @param mtd MTD device structure
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* @param bd descriptor for the good/bad block search pattern
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*
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* The function checks, if a bad block table(s) is/are already
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* available. If not it scans the device for manufacturer
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* marked good / bad blocks and writes the bad block table(s) to
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* the selected place.
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*
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* The bad block table memory is allocated here. It is freed
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* by the onenand_release function.
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*
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*/
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int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)
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{
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struct onenand_chip *this = mtd->priv;
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struct bbm_info *bbm = this->bbm;
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int len, ret = 0;
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len = this->chipsize >> (this->erase_shift + 2);
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/* Allocate memory (2bit per block) and clear the memory bad block table */
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bbm->bbt = kzalloc(len, GFP_KERNEL);
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if (!bbm->bbt) {
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printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");
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return -ENOMEM;
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}
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/* Set the bad block position */
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bbm->badblockpos = ONENAND_BADBLOCK_POS;
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/* Set erase shift */
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bbm->bbt_erase_shift = this->erase_shift;
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if (!bbm->isbad_bbt)
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bbm->isbad_bbt = onenand_isbad_bbt;
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/* Scan the device to build a memory based bad block table */
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if ((ret = onenand_memory_bbt(mtd, bd))) {
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printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");
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kfree(bbm->bbt);
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bbm->bbt = NULL;
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}
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return ret;
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}
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/*
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* Define some generic bad / good block scan pattern which are used
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* while scanning a device for factory marked good / bad blocks.
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*/
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static uint8_t scan_ff_pattern[] = { 0xff, 0xff };
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static struct nand_bbt_descr largepage_memorybased = {
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.options = 0,
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.offs = 0,
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.len = 2,
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.pattern = scan_ff_pattern,
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};
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/**
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* onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device
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* @param mtd MTD device structure
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*
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* This function selects the default bad block table
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* support for the device and calls the onenand_scan_bbt function
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*/
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int onenand_default_bbt(struct mtd_info *mtd)
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{
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struct onenand_chip *this = mtd->priv;
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struct bbm_info *bbm;
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this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL);
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if (!this->bbm)
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return -ENOMEM;
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bbm = this->bbm;
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/* 1KB page has same configuration as 2KB page */
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if (!bbm->badblock_pattern)
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bbm->badblock_pattern = &largepage_memorybased;
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return onenand_scan_bbt(mtd, bbm->badblock_pattern);
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}
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EXPORT_SYMBOL(onenand_scan_bbt);
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EXPORT_SYMBOL(onenand_default_bbt);
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