Subversion Repositories test_project

/*

 *  linux/drivers/mtd/onenand/onenand_bbt.c

 *

 *  Bad Block Table support for the OneNAND driver

 *

 *  Copyright(c) 2005 Samsung Electronics

 *  Kyungmin Park <kyungmin.park@samsung.com>

 *

 *  Derived from nand_bbt.c

 *

 *  TODO:

 *    Split BBT core and chip specific BBT.

 */

#include <linux/slab.h>

#include <linux/mtd/mtd.h>

#include <linux/mtd/onenand.h>

#include <linux/mtd/compatmac.h>

extern int onenand_bbt_read_oob(struct mtd_info *mtd, loff_t from,

                                struct mtd_oob_ops *ops);

/**

 * check_short_pattern - [GENERIC] check if a pattern is in the buffer

 * @param buf           the buffer to search

 * @param len           the length of buffer to search

 * @param paglen        the pagelength

 * @param td            search pattern descriptor

 *

 * Check for a pattern at the given place. Used to search bad block

 * tables and good / bad block identifiers. Same as check_pattern, but

 * no optional empty check and the pattern is expected to start

 * at offset 0.

 *

 */

static int check_short_pattern(uint8_t *buf, int len, int paglen, struct nand_bbt_descr *td)

{

        int i;

        uint8_t *p = buf;

        /* Compare the pattern */

        for (i = 0; i < td->len; i++) {

                if (p[i] != td->pattern[i])

                        return -1;

        }

        return 0;

}

/**

 * create_bbt - [GENERIC] Create a bad block table by scanning the device

 * @param mtd           MTD device structure

 * @param buf           temporary buffer

 * @param bd            descriptor for the good/bad block search pattern

 * @param chip          create the table for a specific chip, -1 read all chips.

 *              Applies only if NAND_BBT_PERCHIP option is set

 *

 * Create a bad block table by scanning the device

 * for the given good/bad block identify pattern

 */

static int create_bbt(struct mtd_info *mtd, uint8_t *buf, struct nand_bbt_descr *bd, int chip)

{

        struct onenand_chip *this = mtd->priv;

        struct bbm_info *bbm = this->bbm;

        int i, j, numblocks, len, scanlen;

        int startblock;

        loff_t from;

        size_t readlen, ooblen;

        struct mtd_oob_ops ops;

        printk(KERN_INFO "Scanning device for bad blocks\n");

        len = 2;

        /* We need only read few bytes from the OOB area */

        scanlen = ooblen = 0;

        readlen = bd->len;

        /* chip == -1 case only */

        /* Note that numblocks is 2 * (real numblocks) here;

         * see i += 2 below as it makses shifting and masking less painful

         */

        numblocks = mtd->size >> (bbm->bbt_erase_shift - 1);

        startblock = 0;

        from = 0;

        ops.mode = MTD_OOB_PLACE;

        ops.ooblen = readlen;

        ops.oobbuf = buf;

        ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;

        for (i = startblock; i < numblocks; ) {

                int ret;

                for (j = 0; j < len; j++) {

                        /* No need to read pages fully,

                         * just read required OOB bytes */

                        ret = onenand_bbt_read_oob(mtd, from + j * mtd->writesize + bd->offs, &ops);

                        /* If it is a initial bad block, just ignore it */

                        if (ret == ONENAND_BBT_READ_FATAL_ERROR)

                                return -EIO;

                        if (ret || check_short_pattern(&buf[j * scanlen], scanlen, mtd->writesize, bd)) {

                                bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);

                                printk(KERN_WARNING "Bad eraseblock %d at 0x%08x\n",

                                        i >> 1, (unsigned int) from);

                                mtd->ecc_stats.badblocks++;

                                break;

                        }

                }

                i += 2;

                from += (1 << bbm->bbt_erase_shift);

        }

        return 0;

}

/**

 * onenand_memory_bbt - [GENERIC] create a memory based bad block table

 * @param mtd           MTD device structure

 * @param bd            descriptor for the good/bad block search pattern

 *

 * The function creates a memory based bbt by scanning the device

 * for manufacturer / software marked good / bad blocks

 */

static inline int onenand_memory_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd)

{

        struct onenand_chip *this = mtd->priv;

        bd->options &= ~NAND_BBT_SCANEMPTY;

        return create_bbt(mtd, this->page_buf, bd, -1);

}

/**

 * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad

 * @param mtd           MTD device structure

 * @param offs          offset in the device

 * @param allowbbt      allow access to bad block table region

 */

static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt)

{

        struct onenand_chip *this = mtd->priv;

        struct bbm_info *bbm = this->bbm;

        int block;

        uint8_t res;

        /* Get block number * 2 */

        block = (int) (offs >> (bbm->bbt_erase_shift - 1));

        res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;

        DEBUG(MTD_DEBUG_LEVEL2, "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",

                (unsigned int) offs, block >> 1, res);

        switch ((int) res) {

        case 0x00:      return 0;

        case 0x01:      return 1;

        case 0x02:      return allowbbt ? 0 : 1;

        }

        return 1;

}

/**

 * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s)

 * @param mtd           MTD device structure

 * @param bd            descriptor for the good/bad block search pattern

 *

 * The function checks, if a bad block table(s) is/are already

 * available. If not it scans the device for manufacturer

 * marked good / bad blocks and writes the bad block table(s) to

 * the selected place.

 *

 * The bad block table memory is allocated here. It is freed

 * by the onenand_release function.

 *

 */

int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd)

{

        struct onenand_chip *this = mtd->priv;

        struct bbm_info *bbm = this->bbm;

        int len, ret = 0;

        len = mtd->size >> (this->erase_shift + 2);

        /* Allocate memory (2bit per block) and clear the memory bad block table */

        bbm->bbt = kzalloc(len, GFP_KERNEL);

        if (!bbm->bbt) {

                printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");

                return -ENOMEM;

        }

        /* Set the bad block position */

        bbm->badblockpos = ONENAND_BADBLOCK_POS;

        /* Set erase shift */

        bbm->bbt_erase_shift = this->erase_shift;

        if (!bbm->isbad_bbt)

                bbm->isbad_bbt = onenand_isbad_bbt;

        /* Scan the device to build a memory based bad block table */

        if ((ret = onenand_memory_bbt(mtd, bd))) {

                printk(KERN_ERR "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");

                kfree(bbm->bbt);

                bbm->bbt = NULL;

        }

        return ret;

}

/*

 * Define some generic bad / good block scan pattern which are used

 * while scanning a device for factory marked good / bad blocks.

 */

static uint8_t scan_ff_pattern[] = { 0xff, 0xff };

static struct nand_bbt_descr largepage_memorybased = {

        .options = 0,

        .offs = 0,

        .len = 2,

        .pattern = scan_ff_pattern,

};

/**

 * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device

 * @param mtd           MTD device structure

 *

 * This function selects the default bad block table

 * support for the device and calls the onenand_scan_bbt function

 */

int onenand_default_bbt(struct mtd_info *mtd)

{

        struct onenand_chip *this = mtd->priv;

        struct bbm_info *bbm;

        this->bbm = kzalloc(sizeof(struct bbm_info), GFP_KERNEL);

        if (!this->bbm)

                return -ENOMEM;

        bbm = this->bbm;

        /* 1KB page has same configuration as 2KB page */

        if (!bbm->badblock_pattern)

                bbm->badblock_pattern = &largepage_memorybased;

        return onenand_scan_bbt(mtd, bbm->badblock_pattern);

}

EXPORT_SYMBOL(onenand_scan_bbt);

EXPORT_SYMBOL(onenand_default_bbt);