/*
 *  Copyright © 2005-2009 Samsung Electronics
 *  Copyright © 2007 Nokia Corporation
 *
 *  Kyungmin Park <kyungmin.park@samsung.com>
 *
 *  Credits:
 *      Adrian Hunter <ext-adrian.hunter@nokia.com>:
 *      auto-placement support, read-while load support, various fixes
 *
 *      Vishak G <vishak.g at samsung.com>, Rohit Hagargundgi <h.rohit at samsung.com>
 *      Flex-OneNAND support
 *      Amul Kumar Saha <amul.saha at samsung.com>
 *      OTP support
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/onenand.h>
#include <linux/mtd/partitions.h>

#include <asm/io.h>

/*
 * Multiblock erase if number of blocks to erase is 2 or more.
 * Maximum number of blocks for simultaneous erase is 64.
 */
#define MB_ERASE_MIN_BLK_COUNT 2
#define MB_ERASE_MAX_BLK_COUNT 64

/* Default Flex-OneNAND boundary and lock respectively */
static int flex_bdry[MAX_DIES * 2] = { -1, 0, -1, 0 };

module_param_array(flex_bdry, int, NULL, 0400);
MODULE_PARM_DESC(flex_bdry,     "SLC Boundary information for Flex-OneNAND"
                                "Syntax:flex_bdry=DIE_BDRY,LOCK,..."
                                "DIE_BDRY: SLC boundary of the die"
                                "LOCK: Locking information for SLC boundary"
                                "    : 0->Set boundary in unlocked status"
                                "    : 1->Set boundary in locked status");

/* Default OneNAND/Flex-OneNAND OTP options*/
static int otp;

module_param(otp, int, 0400);
MODULE_PARM_DESC(otp,   "Corresponding behaviour of OneNAND in OTP"
                        "Syntax : otp=LOCK_TYPE"
                        "LOCK_TYPE : Keys issued, for specific OTP Lock type"
                        "          : 0 -> Default (No Blocks Locked)"
                        "          : 1 -> OTP Block lock"
                        "          : 2 -> 1st Block lock"
                        "          : 3 -> BOTH OTP Block and 1st Block lock");

/*
 * flexonenand_oob_128 - oob info for Flex-Onenand with 4KB page
 * For now, we expose only 64 out of 80 ecc bytes
 */
static int flexonenand_ooblayout_ecc(struct mtd_info *mtd, int section,
                                     struct mtd_oob_region *oobregion)
{
        if (section > 7)
                return -ERANGE;

        oobregion->offset = (section * 16) + 6;
        oobregion->length = 10;

        return 0;
}

static int flexonenand_ooblayout_free(struct mtd_info *mtd, int section,
                                      struct mtd_oob_region *oobregion)
{
        if (section > 7)
                return -ERANGE;

        oobregion->offset = (section * 16) + 2;
        oobregion->length = 4;

        return 0;
}

static const struct mtd_ooblayout_ops flexonenand_ooblayout_ops = {
        .ecc = flexonenand_ooblayout_ecc,
        .free = flexonenand_ooblayout_free,
};

/*
 * onenand_oob_128 - oob info for OneNAND with 4KB page
 *
 * Based on specification:
 * 4Gb M-die OneNAND Flash (KFM4G16Q4M, KFN8G16Q4M). Rev. 1.3, Apr. 2010
 *
 */
static int onenand_ooblayout_128_ecc(struct mtd_info *mtd, int section,
                                     struct mtd_oob_region *oobregion)
{
        if (section > 7)
                return -ERANGE;

        oobregion->offset = (section * 16) + 7;
        oobregion->length = 9;

        return 0;
}

static int onenand_ooblayout_128_free(struct mtd_info *mtd, int section,
                                      struct mtd_oob_region *oobregion)
{
        if (section >= 8)
                return -ERANGE;

        /*
         * free bytes are using the spare area fields marked as
         * "Managed by internal ECC logic for Logical Sector Number area"
         */
        oobregion->offset = (section * 16) + 2;
        oobregion->length = 3;

        return 0;
}

static const struct mtd_ooblayout_ops onenand_oob_128_ooblayout_ops = {
        .ecc = onenand_ooblayout_128_ecc,
        .free = onenand_ooblayout_128_free,
};

/**
 * onenand_oob_32_64 - oob info for large (2KB) page
 */
static int onenand_ooblayout_32_64_ecc(struct mtd_info *mtd, int section,
                                       struct mtd_oob_region *oobregion)
{
        if (section > 3)
                return -ERANGE;

        oobregion->offset = (section * 16) + 8;
        oobregion->length = 5;

        return 0;
}

static int onenand_ooblayout_32_64_free(struct mtd_info *mtd, int section,
                                        struct mtd_oob_region *oobregion)
{
        int sections = (mtd->oobsize / 32) * 2;

        if (section >= sections)
                return -ERANGE;

        if (section & 1) {
                oobregion->offset = ((section - 1) * 16) + 14;
                oobregion->length = 2;
        } else  {
                oobregion->offset = (section * 16) + 2;
                oobregion->length = 3;
        }

        return 0;
}

static const struct mtd_ooblayout_ops onenand_oob_32_64_ooblayout_ops = {
        .ecc = onenand_ooblayout_32_64_ecc,
        .free = onenand_ooblayout_32_64_free,
};

static const unsigned char ffchars[] = {
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 16 */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 32 */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 48 */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 64 */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 80 */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 96 */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 112 */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 128 */
};

/**
 * onenand_readw - [OneNAND Interface] Read OneNAND register
 * @param addr          address to read
 *
 * Read OneNAND register
 */
static unsigned short onenand_readw(void __iomem *addr)
{
        return readw(addr);
}

/**
 * onenand_writew - [OneNAND Interface] Write OneNAND register with value
 * @param value         value to write
 * @param addr          address to write
 *
 * Write OneNAND register with value
 */
static void onenand_writew(unsigned short value, void __iomem *addr)
{
        writew(value, addr);
}

/**
 * onenand_block_address - [DEFAULT] Get block address
 * @param this          onenand chip data structure
 * @param block         the block
 * @return              translated block address if DDP, otherwise same
 *
 * Setup Start Address 1 Register (F100h)
 */
static int onenand_block_address(struct onenand_chip *this, int block)
{
        /* Device Flash Core select, NAND Flash Block Address */
        if (block & this->density_mask)
                return ONENAND_DDP_CHIP1 | (block ^ this->density_mask);

        return block;
}

/**
 * onenand_bufferram_address - [DEFAULT] Get bufferram address
 * @param this          onenand chip data structure
 * @param block         the block
 * @return              set DBS value if DDP, otherwise 0
 *
 * Setup Start Address 2 Register (F101h) for DDP
 */
static int onenand_bufferram_address(struct onenand_chip *this, int block)
{
        /* Device BufferRAM Select */
        if (block & this->density_mask)
                return ONENAND_DDP_CHIP1;

        return ONENAND_DDP_CHIP0;
}

/**
 * onenand_page_address - [DEFAULT] Get page address
 * @param page          the page address
 * @param sector        the sector address
 * @return              combined page and sector address
 *
 * Setup Start Address 8 Register (F107h)
 */
static int onenand_page_address(int page, int sector)
{
        /* Flash Page Address, Flash Sector Address */
        int fpa, fsa;

        fpa = page & ONENAND_FPA_MASK;
        fsa = sector & ONENAND_FSA_MASK;

        return ((fpa << ONENAND_FPA_SHIFT) | fsa);
}

/**
 * onenand_buffer_address - [DEFAULT] Get buffer address
 * @param dataram1      DataRAM index
 * @param sectors       the sector address
 * @param count         the number of sectors
 * @return              the start buffer value
 *
 * Setup Start Buffer Register (F200h)
 */
static int onenand_buffer_address(int dataram1, int sectors, int count)
{
        int bsa, bsc;

        /* BufferRAM Sector Address */
        bsa = sectors & ONENAND_BSA_MASK;

        if (dataram1)
                bsa |= ONENAND_BSA_DATARAM1;    /* DataRAM1 */
        else
                bsa |= ONENAND_BSA_DATARAM0;    /* DataRAM0 */

        /* BufferRAM Sector Count */
        bsc = count & ONENAND_BSC_MASK;

        return ((bsa << ONENAND_BSA_SHIFT) | bsc);
}

/**
 * flexonenand_block- For given address return block number
 * @param this         - OneNAND device structure
 * @param addr          - Address for which block number is needed
 */
static unsigned flexonenand_block(struct onenand_chip *this, loff_t addr)
{
        unsigned boundary, blk, die = 0;

        if (ONENAND_IS_DDP(this) && addr >= this->diesize[0]) {
                die = 1;
                addr -= this->diesize[0];
        }

        boundary = this->boundary[die];

        blk = addr >> (this->erase_shift - 1);
        if (blk > boundary)
                blk = (blk + boundary + 1) >> 1;

        blk += die ? this->density_mask : 0;
        return blk;
}

inline unsigned onenand_block(struct onenand_chip *this, loff_t addr)
{
        if (!FLEXONENAND(this))
                return addr >> this->erase_shift;
        return flexonenand_block(this, addr);
}

/**
 * flexonenand_addr - Return address of the block
 * @this:               OneNAND device structure
 * @block:              Block number on Flex-OneNAND
 *
 * Return address of the block
 */
static loff_t flexonenand_addr(struct onenand_chip *this, int block)
{
        loff_t ofs = 0;
        int die = 0, boundary;

        if (ONENAND_IS_DDP(this) && block >= this->density_mask) {
                block -= this->density_mask;
                die = 1;
                ofs = this->diesize[0];
        }

        boundary = this->boundary[die];
        ofs += (loff_t)block << (this->erase_shift - 1);
        if (block > (boundary + 1))
                ofs += (loff_t)(block - boundary - 1) << (this->erase_shift - 1);
        return ofs;
}

loff_t onenand_addr(struct onenand_chip *this, int block)
{
        if (!FLEXONENAND(this))
                return (loff_t)block << this->erase_shift;
        return flexonenand_addr(this, block);
}
EXPORT_SYMBOL(onenand_addr);

/**
 * onenand_get_density - [DEFAULT] Get OneNAND density
 * @param dev_id        OneNAND device ID
 *
 * Get OneNAND density from device ID
 */
static inline int onenand_get_density(int dev_id)
{
        int density = dev_id >> ONENAND_DEVICE_DENSITY_SHIFT;
        return (density & ONENAND_DEVICE_DENSITY_MASK);
}

/**
 * flexonenand_region - [Flex-OneNAND] Return erase region of addr
 * @param mtd           MTD device structure
 * @param addr          address whose erase region needs to be identified
 */
int flexonenand_region(struct mtd_info *mtd, loff_t addr)
{
        int i;

        for (i = 0; i < mtd->numeraseregions; i++)
                if (addr < mtd->eraseregions[i].offset)
                        break;
        return i - 1;
}
EXPORT_SYMBOL(flexonenand_region);

/**
 * onenand_command - [DEFAULT] Send command to OneNAND device
 * @param mtd           MTD device structure
 * @param cmd           the command to be sent
 * @param addr          offset to read from or write to
 * @param len           number of bytes to read or write
 *
 * Send command to OneNAND device. This function is used for middle/large page
 * devices (1KB/2KB Bytes per page)
 */
static int onenand_command(struct mtd_info *mtd, int cmd, loff_t addr, size_t len)
{
        struct onenand_chip *this = mtd->priv;
        int value, block, page;

        /* Address translation */
        switch (cmd) {
        case ONENAND_CMD_UNLOCK:
        case ONENAND_CMD_LOCK:
        case ONENAND_CMD_LOCK_TIGHT:
        case ONENAND_CMD_UNLOCK_ALL:
                block = -1;
                page = -1;
                break;

        case FLEXONENAND_CMD_PI_ACCESS:
                /* addr contains die index */
                block = addr * this->density_mask;
                page = -1;
                break;

        case ONENAND_CMD_ERASE:
        case ONENAND_CMD_MULTIBLOCK_ERASE:
        case ONENAND_CMD_ERASE_VERIFY:
        case ONENAND_CMD_BUFFERRAM:
        case ONENAND_CMD_OTP_ACCESS:
                block = onenand_block(this, addr);
                page = -1;
                break;

        case FLEXONENAND_CMD_READ_PI:
                cmd = ONENAND_CMD_READ;
                block = addr * this->density_mask;
                page = 0;
                break;

        default:
                block = onenand_block(this, addr);
                if (FLEXONENAND(this))
                        page = (int) (addr - onenand_addr(this, block))>>\
                                this->page_shift;
                else
                        page = (int) (addr >> this->page_shift);
                if (ONENAND_IS_2PLANE(this)) {
                        /* Make the even block number */
                        block &= ~1;
                        /* Is it the odd plane? */
                        if (addr & this->writesize)
                                block++;
                        page >>= 1;
                }
                page &= this->page_mask;
                break;
        }

        /* NOTE: The setting order of the registers is very important! */
        if (cmd == ONENAND_CMD_BUFFERRAM) {
                /* Select DataRAM for DDP */
                value = onenand_bufferram_address(this, block);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS2);

                if (ONENAND_IS_2PLANE(this) || ONENAND_IS_4KB_PAGE(this))
                        /* It is always BufferRAM0 */
                        ONENAND_SET_BUFFERRAM0(this);
                else
                        /* Switch to the next data buffer */
                        ONENAND_SET_NEXT_BUFFERRAM(this);

                return 0;
        }

        if (block != -1) {
                /* Write 'DFS, FBA' of Flash */
                value = onenand_block_address(this, block);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS1);

                /* Select DataRAM for DDP */
                value = onenand_bufferram_address(this, block);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS2);
        }

        if (page != -1) {
                /* Now we use page size operation */
                int sectors = 0, count = 0;
                int dataram;

                switch (cmd) {
                case FLEXONENAND_CMD_RECOVER_LSB:
                case ONENAND_CMD_READ:
                case ONENAND_CMD_READOOB:
                        if (ONENAND_IS_4KB_PAGE(this))
                                /* It is always BufferRAM0 */
                                dataram = ONENAND_SET_BUFFERRAM0(this);
                        else
                                dataram = ONENAND_SET_NEXT_BUFFERRAM(this);
                        break;

                default:
                        if (ONENAND_IS_2PLANE(this) && cmd == ONENAND_CMD_PROG)
                                cmd = ONENAND_CMD_2X_PROG;
                        dataram = ONENAND_CURRENT_BUFFERRAM(this);
                        break;
                }

                /* Write 'FPA, FSA' of Flash */
                value = onenand_page_address(page, sectors);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS8);

                /* Write 'BSA, BSC' of DataRAM */
                value = onenand_buffer_address(dataram, sectors, count);
                this->write_word(value, this->base + ONENAND_REG_START_BUFFER);
        }

        /* Interrupt clear */
        this->write_word(ONENAND_INT_CLEAR, this->base + ONENAND_REG_INTERRUPT);

        /* Write command */
        this->write_word(cmd, this->base + ONENAND_REG_COMMAND);

        return 0;
}

/**
 * onenand_read_ecc - return ecc status
 * @param this          onenand chip structure
 */
static inline int onenand_read_ecc(struct onenand_chip *this)
{
        int ecc, i, result = 0;

        if (!FLEXONENAND(this) && !ONENAND_IS_4KB_PAGE(this))
                return this->read_word(this->base + ONENAND_REG_ECC_STATUS);

        for (i = 0; i < 4; i++) {
                ecc = this->read_word(this->base + ONENAND_REG_ECC_STATUS + i*2);
                if (likely(!ecc))
                        continue;
                if (ecc & FLEXONENAND_UNCORRECTABLE_ERROR)
                        return ONENAND_ECC_2BIT_ALL;
                else
                        result = ONENAND_ECC_1BIT_ALL;
        }

        return result;
}

/**
 * onenand_wait - [DEFAULT] wait until the command is done
 * @param mtd           MTD device structure
 * @param state         state to select the max. timeout value
 *
 * Wait for command done. This applies to all OneNAND command
 * Read can take up to 30us, erase up to 2ms and program up to 350us
 * according to general OneNAND specs
 */
static int onenand_wait(struct mtd_info *mtd, int state)
{
        struct onenand_chip * this = mtd->priv;
        unsigned long timeout;
        unsigned int flags = ONENAND_INT_MASTER;
        unsigned int interrupt = 0;
        unsigned int ctrl;

        /* The 20 msec is enough */
        timeout = jiffies + msecs_to_jiffies(20);
        while (time_before(jiffies, timeout)) {
                interrupt = this->read_word(this->base + ONENAND_REG_INTERRUPT);

                if (interrupt & flags)
                        break;

                if (state != FL_READING && state != FL_PREPARING_ERASE)
                        cond_resched();
        }
        /* To get correct interrupt status in timeout case */
        interrupt = this->read_word(this->base + ONENAND_REG_INTERRUPT);

        ctrl = this->read_word(this->base + ONENAND_REG_CTRL_STATUS);

        /*
         * In the Spec. it checks the controller status first
         * However if you get the correct information in case of
         * power off recovery (POR) test, it should read ECC status first
         */
        if (interrupt & ONENAND_INT_READ) {
                int ecc = onenand_read_ecc(this);
                if (ecc) {
                        if (ecc & ONENAND_ECC_2BIT_ALL) {
                                printk(KERN_ERR "%s: ECC error = 0x%04x\n",
                                        __func__, ecc);
                                mtd->ecc_stats.failed++;
                                return -EBADMSG;
                        } else if (ecc & ONENAND_ECC_1BIT_ALL) {
                                printk(KERN_DEBUG "%s: correctable ECC error = 0x%04x\n",
                                        __func__, ecc);
                                mtd->ecc_stats.corrected++;
                        }
                }
        } else if (state == FL_READING) {
                printk(KERN_ERR "%s: read timeout! ctrl=0x%04x intr=0x%04x\n",
                        __func__, ctrl, interrupt);
                return -EIO;
        }

        if (state == FL_PREPARING_ERASE && !(interrupt & ONENAND_INT_ERASE)) {
                printk(KERN_ERR "%s: mb erase timeout! ctrl=0x%04x intr=0x%04x\n",
                       __func__, ctrl, interrupt);
                return -EIO;
        }

        if (!(interrupt & ONENAND_INT_MASTER)) {
                printk(KERN_ERR "%s: timeout! ctrl=0x%04x intr=0x%04x\n",
                       __func__, ctrl, interrupt);
                return -EIO;
        }

        /* If there's controller error, it's a real error */
        if (ctrl & ONENAND_CTRL_ERROR) {
                printk(KERN_ERR "%s: controller error = 0x%04x\n",
                        __func__, ctrl);
                if (ctrl & ONENAND_CTRL_LOCK)
                        printk(KERN_ERR "%s: it's locked error.\n", __func__);
                return -EIO;
        }

        return 0;
}

/*
 * onenand_interrupt - [DEFAULT] onenand interrupt handler
 * @param irq           onenand interrupt number
 * @param dev_id        interrupt data
 *
 * complete the work
 */
static irqreturn_t onenand_interrupt(int irq, void *data)
{
        struct onenand_chip *this = data;

        /* To handle shared interrupt */
        if (!this->complete.done)
                complete(&this->complete);

        return IRQ_HANDLED;
}

/*
 * onenand_interrupt_wait - [DEFAULT] wait until the command is done
 * @param mtd           MTD device structure
 * @param state         state to select the max. timeout value
 *
 * Wait for command done.
 */
static int onenand_interrupt_wait(struct mtd_info *mtd, int state)
{
        struct onenand_chip *this = mtd->priv;

        wait_for_completion(&this->complete);

        return onenand_wait(mtd, state);
}

/*
 * onenand_try_interrupt_wait - [DEFAULT] try interrupt wait
 * @param mtd           MTD device structure
 * @param state         state to select the max. timeout value
 *
 * Try interrupt based wait (It is used one-time)
 */
static int onenand_try_interrupt_wait(struct mtd_info *mtd, int state)
{
        struct onenand_chip *this = mtd->priv;
        unsigned long remain, timeout;

        /* We use interrupt wait first */
        this->wait = onenand_interrupt_wait;

        timeout = msecs_to_jiffies(100);
        remain = wait_for_completion_timeout(&this->complete, timeout);
        if (!remain) {
                printk(KERN_INFO "OneNAND: There's no interrupt. "
                                "We use the normal wait\n");

                /* Release the irq */
                free_irq(this->irq, this);

                this->wait = onenand_wait;
        }

        return onenand_wait(mtd, state);
}

/*
 * onenand_setup_wait - [OneNAND Interface] setup onenand wait method
 * @param mtd           MTD device structure
 *
 * There's two method to wait onenand work
 * 1. polling - read interrupt status register
 * 2. interrupt - use the kernel interrupt method
 */
static void onenand_setup_wait(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;
        int syscfg;

        init_completion(&this->complete);

        if (this->irq <= 0) {
                this->wait = onenand_wait;
                return;
        }

        if (request_irq(this->irq, &onenand_interrupt,
                                IRQF_SHARED, "onenand", this)) {
                /* If we can't get irq, use the normal wait */
                this->wait = onenand_wait;
                return;
        }

        /* Enable interrupt */
        syscfg = this->read_word(this->base + ONENAND_REG_SYS_CFG1);
        syscfg |= ONENAND_SYS_CFG1_IOBE;
        this->write_word(syscfg, this->base + ONENAND_REG_SYS_CFG1);

        this->wait = onenand_try_interrupt_wait;
}

/**
 * onenand_bufferram_offset - [DEFAULT] BufferRAM offset
 * @param mtd           MTD data structure
 * @param area          BufferRAM area
 * @return              offset given area
 *
 * Return BufferRAM offset given area
 */
static inline int onenand_bufferram_offset(struct mtd_info *mtd, int area)
{
        struct onenand_chip *this = mtd->priv;

        if (ONENAND_CURRENT_BUFFERRAM(this)) {
                /* Note: the 'this->writesize' is a real page size */
                if (area == ONENAND_DATARAM)
                        return this->writesize;
                if (area == ONENAND_SPARERAM)
                        return mtd->oobsize;
        }

        return 0;
}

/**
 * onenand_read_bufferram - [OneNAND Interface] Read the bufferram area
 * @param mtd           MTD data structure
 * @param area          BufferRAM area
 * @param buffer        the databuffer to put/get data
 * @param offset        offset to read from or write to
 * @param count         number of bytes to read/write
 *
 * Read the BufferRAM area
 */
static int onenand_read_bufferram(struct mtd_info *mtd, int area,
                unsigned char *buffer, int offset, size_t count)
{
        struct onenand_chip *this = mtd->priv;
        void __iomem *bufferram;

        bufferram = this->base + area;

        bufferram += onenand_bufferram_offset(mtd, area);

        if (ONENAND_CHECK_BYTE_ACCESS(count)) {
                unsigned short word;

                /* Align with word(16-bit) size */
                count--;

                /* Read word and save byte */
                word = this->read_word(bufferram + offset + count);
                buffer[count] = (word & 0xff);
        }

        memcpy(buffer, bufferram + offset, count);

        return 0;
}

/**
 * onenand_sync_read_bufferram - [OneNAND Interface] Read the bufferram area with Sync. Burst mode
 * @param mtd           MTD data structure
 * @param area          BufferRAM area
 * @param buffer        the databuffer to put/get data
 * @param offset        offset to read from or write to
 * @param count         number of bytes to read/write
 *
 * Read the BufferRAM area with Sync. Burst Mode
 */
static int onenand_sync_read_bufferram(struct mtd_info *mtd, int area,
                unsigned char *buffer, int offset, size_t count)
{
        struct onenand_chip *this = mtd->priv;
        void __iomem *bufferram;

        bufferram = this->base + area;

        bufferram += onenand_bufferram_offset(mtd, area);

        this->mmcontrol(mtd, ONENAND_SYS_CFG1_SYNC_READ);

        if (ONENAND_CHECK_BYTE_ACCESS(count)) {
                unsigned short word;

                /* Align with word(16-bit) size */
                count--;

                /* Read word and save byte */
                word = this->read_word(bufferram + offset + count);
                buffer[count] = (word & 0xff);
        }

        memcpy(buffer, bufferram + offset, count);

        this->mmcontrol(mtd, 0);

        return 0;
}

/**
 * onenand_write_bufferram - [OneNAND Interface] Write the bufferram area
 * @param mtd           MTD data structure
 * @param area          BufferRAM area
 * @param buffer        the databuffer to put/get data
 * @param offset        offset to read from or write to
 * @param count         number of bytes to read/write
 *
 * Write the BufferRAM area
 */
static int onenand_write_bufferram(struct mtd_info *mtd, int area,
                const unsigned char *buffer, int offset, size_t count)
{
        struct onenand_chip *this = mtd->priv;
        void __iomem *bufferram;

        bufferram = this->base + area;

        bufferram += onenand_bufferram_offset(mtd, area);

        if (ONENAND_CHECK_BYTE_ACCESS(count)) {
                unsigned short word;
                int byte_offset;

                /* Align with word(16-bit) size */
                count--;

                /* Calculate byte access offset */
                byte_offset = offset + count;

                /* Read word and save byte */
                word = this->read_word(bufferram + byte_offset);
                word = (word & ~0xff) | buffer[count];
                this->write_word(word, bufferram + byte_offset);
        }

        memcpy(bufferram + offset, buffer, count);

        return 0;
}

/**
 * onenand_get_2x_blockpage - [GENERIC] Get blockpage at 2x program mode
 * @param mtd           MTD data structure
 * @param addr          address to check
 * @return              blockpage address
 *
 * Get blockpage address at 2x program mode
 */
static int onenand_get_2x_blockpage(struct mtd_info *mtd, loff_t addr)
{
        struct onenand_chip *this = mtd->priv;
        int blockpage, block, page;

        /* Calculate the even block number */
        block = (int) (addr >> this->erase_shift) & ~1;
        /* Is it the odd plane? */
        if (addr & this->writesize)
                block++;
        page = (int) (addr >> (this->page_shift + 1)) & this->page_mask;
        blockpage = (block << 7) | page;

        return blockpage;
}

/**
 * onenand_check_bufferram - [GENERIC] Check BufferRAM information
 * @param mtd           MTD data structure
 * @param addr          address to check
 * @return              1 if there are valid data, otherwise 0
 *
 * Check bufferram if there is data we required
 */
static int onenand_check_bufferram(struct mtd_info *mtd, loff_t addr)
{
        struct onenand_chip *this = mtd->priv;
        int blockpage, found = 0;
        unsigned int i;

        if (ONENAND_IS_2PLANE(this))
                blockpage = onenand_get_2x_blockpage(mtd, addr);
        else
                blockpage = (int) (addr >> this->page_shift);

        /* Is there valid data? */
        i = ONENAND_CURRENT_BUFFERRAM(this);
        if (this->bufferram[i].blockpage == blockpage)
                found = 1;
        else {
                /* Check another BufferRAM */
                i = ONENAND_NEXT_BUFFERRAM(this);
                if (this->bufferram[i].blockpage == blockpage) {
                        ONENAND_SET_NEXT_BUFFERRAM(this);
                        found = 1;
                }
        }

        if (found && ONENAND_IS_DDP(this)) {
                /* Select DataRAM for DDP */
                int block = onenand_block(this, addr);
                int value = onenand_bufferram_address(this, block);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS2);
        }

        return found;
}

/**
 * onenand_update_bufferram - [GENERIC] Update BufferRAM information
 * @param mtd           MTD data structure
 * @param addr          address to update
 * @param valid         valid flag
 *
 * Update BufferRAM information
 */
static void onenand_update_bufferram(struct mtd_info *mtd, loff_t addr,
                int valid)
{
        struct onenand_chip *this = mtd->priv;
        int blockpage;
        unsigned int i;

        if (ONENAND_IS_2PLANE(this))
                blockpage = onenand_get_2x_blockpage(mtd, addr);
        else
                blockpage = (int) (addr >> this->page_shift);

        /* Invalidate another BufferRAM */
        i = ONENAND_NEXT_BUFFERRAM(this);
        if (this->bufferram[i].blockpage == blockpage)
                this->bufferram[i].blockpage = -1;

        /* Update BufferRAM */
        i = ONENAND_CURRENT_BUFFERRAM(this);
        if (valid)
                this->bufferram[i].blockpage = blockpage;
        else
                this->bufferram[i].blockpage = -1;
}

/**
 * onenand_invalidate_bufferram - [GENERIC] Invalidate BufferRAM information
 * @param mtd           MTD data structure
 * @param addr          start address to invalidate
 * @param len           length to invalidate
 *
 * Invalidate BufferRAM information
 */
static void onenand_invalidate_bufferram(struct mtd_info *mtd, loff_t addr,
                unsigned int len)
{
        struct onenand_chip *this = mtd->priv;
        int i;
        loff_t end_addr = addr + len;

        /* Invalidate BufferRAM */
        for (i = 0; i < MAX_BUFFERRAM; i++) {
                loff_t buf_addr = this->bufferram[i].blockpage << this->page_shift;
                if (buf_addr >= addr && buf_addr < end_addr)
                        this->bufferram[i].blockpage = -1;
        }
}

/**
 * onenand_get_device - [GENERIC] Get chip for selected access
 * @param mtd           MTD device structure
 * @param new_state     the state which is requested
 *
 * Get the device and lock it for exclusive access
 */
static int onenand_get_device(struct mtd_info *mtd, int new_state)
{
        struct onenand_chip *this = mtd->priv;
        DECLARE_WAITQUEUE(wait, current);

        /*
         * Grab the lock and see if the device is available
         */
        while (1) {
                spin_lock(&this->chip_lock);
                if (this->state == FL_READY) {
                        this->state = new_state;
                        spin_unlock(&this->chip_lock);
                        if (new_state != FL_PM_SUSPENDED && this->enable)
                                this->enable(mtd);
                        break;
                }
                if (new_state == FL_PM_SUSPENDED) {
                        spin_unlock(&this->chip_lock);
                        return (this->state == FL_PM_SUSPENDED) ? 0 : -EAGAIN;
                }
                set_current_state(TASK_UNINTERRUPTIBLE);
                add_wait_queue(&this->wq, &wait);
                spin_unlock(&this->chip_lock);
                schedule();
                remove_wait_queue(&this->wq, &wait);
        }

        return 0;
}

/**
 * onenand_release_device - [GENERIC] release chip
 * @param mtd           MTD device structure
 *
 * Deselect, release chip lock and wake up anyone waiting on the device
 */
static void onenand_release_device(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;

        if (this->state != FL_PM_SUSPENDED && this->disable)
                this->disable(mtd);
        /* Release the chip */
        spin_lock(&this->chip_lock);
        this->state = FL_READY;
        wake_up(&this->wq);
        spin_unlock(&this->chip_lock);
}

/**
 * onenand_transfer_auto_oob - [INTERN] oob auto-placement transfer
 * @param mtd           MTD device structure
 * @param buf           destination address
 * @param column        oob offset to read from
 * @param thislen       oob length to read
 */
static int onenand_transfer_auto_oob(struct mtd_info *mtd, uint8_t *buf, int column,
                                int thislen)
{
        struct onenand_chip *this = mtd->priv;
        int ret;

        this->read_bufferram(mtd, ONENAND_SPARERAM, this->oob_buf, 0,
                             mtd->oobsize);
        ret = mtd_ooblayout_get_databytes(mtd, buf, this->oob_buf,
                                          column, thislen);
        if (ret)
                return ret;

        return 0;
}

/**
 * onenand_recover_lsb - [Flex-OneNAND] Recover LSB page data
 * @param mtd           MTD device structure
 * @param addr          address to recover
 * @param status        return value from onenand_wait / onenand_bbt_wait
 *
 * MLC NAND Flash cell has paired pages - LSB page and MSB page. LSB page has
 * lower page address and MSB page has higher page address in paired pages.
 * If power off occurs during MSB page program, the paired LSB page data can
 * become corrupt. LSB page recovery read is a way to read LSB page though page
 * data are corrupted. When uncorrectable error occurs as a result of LSB page
 * read after power up, issue LSB page recovery read.
 */
static int onenand_recover_lsb(struct mtd_info *mtd, loff_t addr, int status)
{
        struct onenand_chip *this = mtd->priv;
        int i;

        /* Recovery is only for Flex-OneNAND */
        if (!FLEXONENAND(this))
                return status;

        /* check if we failed due to uncorrectable error */
        if (!mtd_is_eccerr(status) && status != ONENAND_BBT_READ_ECC_ERROR)
                return status;

        /* check if address lies in MLC region */
        i = flexonenand_region(mtd, addr);
        if (mtd->eraseregions[i].erasesize < (1 << this->erase_shift))
                return status;

        /* We are attempting to reread, so decrement stats.failed
         * which was incremented by onenand_wait due to read failure
         */
        printk(KERN_INFO "%s: Attempting to recover from uncorrectable read\n",
                __func__);
        mtd->ecc_stats.failed--;

        /* Issue the LSB page recovery command */
        this->command(mtd, FLEXONENAND_CMD_RECOVER_LSB, addr, this->writesize);
        return this->wait(mtd, FL_READING);
}

/**
 * onenand_mlc_read_ops_nolock - MLC OneNAND read main and/or out-of-band
 * @param mtd           MTD device structure
 * @param from          offset to read from
 * @param ops:          oob operation description structure
 *
 * MLC OneNAND / Flex-OneNAND has 4KB page size and 4KB dataram.
 * So, read-while-load is not present.
 */
static int onenand_mlc_read_ops_nolock(struct mtd_info *mtd, loff_t from,
                                struct mtd_oob_ops *ops)
{
        struct onenand_chip *this = mtd->priv;
        struct mtd_ecc_stats stats;
        size_t len = ops->len;
        size_t ooblen = ops->ooblen;
        u_char *buf = ops->datbuf;
        u_char *oobbuf = ops->oobbuf;
        int read = 0, column, thislen;
        int oobread = 0, oobcolumn, thisooblen, oobsize;
        int ret = 0;
        int writesize = this->writesize;

        pr_debug("%s: from = 0x%08x, len = %i\n", __func__, (unsigned int)from,
                        (int)len);

        oobsize = mtd_oobavail(mtd, ops);
        oobcolumn = from & (mtd->oobsize - 1);

        /* Do not allow reads past end of device */
        if (from + len > mtd->size) {
                printk(KERN_ERR "%s: Attempt read beyond end of device\n",
                        __func__);
                ops->retlen = 0;
                ops->oobretlen = 0;
                return -EINVAL;
        }

        stats = mtd->ecc_stats;

        while (read < len) {
                cond_resched();

                thislen = min_t(int, writesize, len - read);

                column = from & (writesize - 1);
                if (column + thislen > writesize)
                        thislen = writesize - column;

                if (!onenand_check_bufferram(mtd, from)) {
                        this->command(mtd, ONENAND_CMD_READ, from, writesize);

                        ret = this->wait(mtd, FL_READING);
                        if (unlikely(ret))
                                ret = onenand_recover_lsb(mtd, from, ret);
                        onenand_update_bufferram(mtd, from, !ret);
                        if (mtd_is_eccerr(ret))
                                ret = 0;
                        if (ret)
                                break;
                }

                this->read_bufferram(mtd, ONENAND_DATARAM, buf, column, thislen);
                if (oobbuf) {
                        thisooblen = oobsize - oobcolumn;
                        thisooblen = min_t(int, thisooblen, ooblen - oobread);

                        if (ops->mode == MTD_OPS_AUTO_OOB)
                                onenand_transfer_auto_oob(mtd, oobbuf, oobcolumn, thisooblen);
                        else
                                this->read_bufferram(mtd, ONENAND_SPARERAM, oobbuf, oobcolumn, thisooblen);
                        oobread += thisooblen;
                        oobbuf += thisooblen;
                        oobcolumn = 0;
                }

                read += thislen;
                if (read == len)
                        break;

                from += thislen;
                buf += thislen;
        }

        /*
         * Return success, if no ECC failures, else -EBADMSG
         * fs driver will take care of that, because
         * retlen == desired len and result == -EBADMSG
         */
        ops->retlen = read;
        ops->oobretlen = oobread;

        if (ret)
                return ret;

        if (mtd->ecc_stats.failed - stats.failed)
                return -EBADMSG;

        /* return max bitflips per ecc step; ONENANDs correct 1 bit only */
        return mtd->ecc_stats.corrected != stats.corrected ? 1 : 0;
}

/**
 * onenand_read_ops_nolock - [OneNAND Interface] OneNAND read main and/or out-of-band
 * @param mtd           MTD device structure
 * @param from          offset to read from
 * @param ops:          oob operation description structure
 *
 * OneNAND read main and/or out-of-band data
 */
static int onenand_read_ops_nolock(struct mtd_info *mtd, loff_t from,
                                struct mtd_oob_ops *ops)
{
        struct onenand_chip *this = mtd->priv;
        struct mtd_ecc_stats stats;
        size_t len = ops->len;
        size_t ooblen = ops->ooblen;
        u_char *buf = ops->datbuf;
        u_char *oobbuf = ops->oobbuf;
        int read = 0, column, thislen;
        int oobread = 0, oobcolumn, thisooblen, oobsize;
        int ret = 0, boundary = 0;
        int writesize = this->writesize;

        pr_debug("%s: from = 0x%08x, len = %i\n", __func__, (unsigned int)from,
                        (int)len);

        oobsize = mtd_oobavail(mtd, ops);
        oobcolumn = from & (mtd->oobsize - 1);

        /* Do not allow reads past end of device */
        if ((from + len) > mtd->size) {
                printk(KERN_ERR "%s: Attempt read beyond end of device\n",
                        __func__);
                ops->retlen = 0;
                ops->oobretlen = 0;
                return -EINVAL;
        }

        stats = mtd->ecc_stats;

        /* Read-while-load method */

        /* Do first load to bufferRAM */
        if (read < len) {
                if (!onenand_check_bufferram(mtd, from)) {
                        this->command(mtd, ONENAND_CMD_READ, from, writesize);
                        ret = this->wait(mtd, FL_READING);
                        onenand_update_bufferram(mtd, from, !ret);
                        if (mtd_is_eccerr(ret))
                                ret = 0;
                }
        }

        thislen = min_t(int, writesize, len - read);
        column = from & (writesize - 1);
        if (column + thislen > writesize)
                thislen = writesize - column;

        while (!ret) {
                /* If there is more to load then start next load */
                from += thislen;
                if (read + thislen < len) {
                        this->command(mtd, ONENAND_CMD_READ, from, writesize);
                        /*
                         * Chip boundary handling in DDP
                         * Now we issued chip 1 read and pointed chip 1
                         * bufferram so we have to point chip 0 bufferram.
                         */
                        if (ONENAND_IS_DDP(this) &&
                            unlikely(from == (this->chipsize >> 1))) {
                                this->write_word(ONENAND_DDP_CHIP0, this->base + ONENAND_REG_START_ADDRESS2);
                                boundary = 1;
                        } else
                                boundary = 0;
                        ONENAND_SET_PREV_BUFFERRAM(this);
                }
                /* While load is going, read from last bufferRAM */
                this->read_bufferram(mtd, ONENAND_DATARAM, buf, column, thislen);

                /* Read oob area if needed */
                if (oobbuf) {
                        thisooblen = oobsize - oobcolumn;
                        thisooblen = min_t(int, thisooblen, ooblen - oobread);

                        if (ops->mode == MTD_OPS_AUTO_OOB)
                                onenand_transfer_auto_oob(mtd, oobbuf, oobcolumn, thisooblen);
                        else
                                this->read_bufferram(mtd, ONENAND_SPARERAM, oobbuf, oobcolumn, thisooblen);
                        oobread += thisooblen;
                        oobbuf += thisooblen;
                        oobcolumn = 0;
                }

                /* See if we are done */
                read += thislen;
                if (read == len)
                        break;
                /* Set up for next read from bufferRAM */
                if (unlikely(boundary))
                        this->write_word(ONENAND_DDP_CHIP1, this->base + ONENAND_REG_START_ADDRESS2);
                ONENAND_SET_NEXT_BUFFERRAM(this);
                buf += thislen;
                thislen = min_t(int, writesize, len - read);
                column = 0;
                cond_resched();
                /* Now wait for load */
                ret = this->wait(mtd, FL_READING);
                onenand_update_bufferram(mtd, from, !ret);
                if (mtd_is_eccerr(ret))
                        ret = 0;
        }

        /*
         * Return success, if no ECC failures, else -EBADMSG
         * fs driver will take care of that, because
         * retlen == desired len and result == -EBADMSG
         */
        ops->retlen = read;
        ops->oobretlen = oobread;

        if (ret)
                return ret;

        if (mtd->ecc_stats.failed - stats.failed)
                return -EBADMSG;

        /* return max bitflips per ecc step; ONENANDs correct 1 bit only */
        return mtd->ecc_stats.corrected != stats.corrected ? 1 : 0;
}

/**
 * onenand_read_oob_nolock - [MTD Interface] OneNAND read out-of-band
 * @param mtd           MTD device structure
 * @param from          offset to read from
 * @param ops:          oob operation description structure
 *
 * OneNAND read out-of-band data from the spare area
 */
static int onenand_read_oob_nolock(struct mtd_info *mtd, loff_t from,
                        struct mtd_oob_ops *ops)
{
        struct onenand_chip *this = mtd->priv;
        struct mtd_ecc_stats stats;
        int read = 0, thislen, column, oobsize;
        size_t len = ops->ooblen;
        unsigned int mode = ops->mode;
        u_char *buf = ops->oobbuf;
        int ret = 0, readcmd;

        from += ops->ooboffs;

        pr_debug("%s: from = 0x%08x, len = %i\n", __func__, (unsigned int)from,
                        (int)len);

        /* Initialize return length value */
        ops->oobretlen = 0;

        if (mode == MTD_OPS_AUTO_OOB)
                oobsize = mtd->oobavail;
        else
                oobsize = mtd->oobsize;

        column = from & (mtd->oobsize - 1);

        if (unlikely(column >= oobsize)) {
                printk(KERN_ERR "%s: Attempted to start read outside oob\n",
                        __func__);
                return -EINVAL;
        }

        stats = mtd->ecc_stats;

        readcmd = ONENAND_IS_4KB_PAGE(this) ? ONENAND_CMD_READ : ONENAND_CMD_READOOB;

        while (read < len) {
                cond_resched();

                thislen = oobsize - column;
                thislen = min_t(int, thislen, len);

                this->command(mtd, readcmd, from, mtd->oobsize);

                onenand_update_bufferram(mtd, from, 0);

                ret = this->wait(mtd, FL_READING);
                if (unlikely(ret))
                        ret = onenand_recover_lsb(mtd, from, ret);

                if (ret && !mtd_is_eccerr(ret)) {
                        printk(KERN_ERR "%s: read failed = 0x%x\n",
                                __func__, ret);
                        break;
                }

                if (mode == MTD_OPS_AUTO_OOB)
                        onenand_transfer_auto_oob(mtd, buf, column, thislen);
                else
                        this->read_bufferram(mtd, ONENAND_SPARERAM, buf, column, thislen);

                read += thislen;

                if (read == len)
                        break;

                buf += thislen;

                /* Read more? */
                if (read < len) {
                        /* Page size */
                        from += mtd->writesize;
                        column = 0;
                }
        }

        ops->oobretlen = read;

        if (ret)
                return ret;

        if (mtd->ecc_stats.failed - stats.failed)
                return -EBADMSG;

        return 0;
}

/**
 * onenand_read_oob - [MTD Interface] Read main and/or out-of-band
 * @param mtd:          MTD device structure
 * @param from:         offset to read from
 * @param ops:          oob operation description structure

 * Read main and/or out-of-band
 */
static int onenand_read_oob(struct mtd_info *mtd, loff_t from,
                            struct mtd_oob_ops *ops)
{
        struct onenand_chip *this = mtd->priv;
        int ret;

        switch (ops->mode) {
        case MTD_OPS_PLACE_OOB:
        case MTD_OPS_AUTO_OOB:
                break;
        case MTD_OPS_RAW:
                /* Not implemented yet */
        default:
                return -EINVAL;
        }

        onenand_get_device(mtd, FL_READING);
        if (ops->datbuf)
                ret = ONENAND_IS_4KB_PAGE(this) ?
                        onenand_mlc_read_ops_nolock(mtd, from, ops) :
                        onenand_read_ops_nolock(mtd, from, ops);
        else
                ret = onenand_read_oob_nolock(mtd, from, ops);
        onenand_release_device(mtd);

        return ret;
}

/**
 * onenand_bbt_wait - [DEFAULT] wait until the command is done
 * @param mtd           MTD device structure
 * @param state         state to select the max. timeout value
 *
 * Wait for command done.
 */
static int onenand_bbt_wait(struct mtd_info *mtd, int state)
{
        struct onenand_chip *this = mtd->priv;
        unsigned long timeout;
        unsigned int interrupt, ctrl, ecc, addr1, addr8;

        /* The 20 msec is enough */
        timeout = jiffies + msecs_to_jiffies(20);
        while (time_before(jiffies, timeout)) {
                interrupt = this->read_word(this->base + ONENAND_REG_INTERRUPT);
                if (interrupt & ONENAND_INT_MASTER)
                        break;
        }
        /* To get correct interrupt status in timeout case */
        interrupt = this->read_word(this->base + ONENAND_REG_INTERRUPT);
        ctrl = this->read_word(this->base + ONENAND_REG_CTRL_STATUS);
        addr1 = this->read_word(this->base + ONENAND_REG_START_ADDRESS1);
        addr8 = this->read_word(this->base + ONENAND_REG_START_ADDRESS8);

        if (interrupt & ONENAND_INT_READ) {
                ecc = onenand_read_ecc(this);
                if (ecc & ONENAND_ECC_2BIT_ALL) {
                        printk(KERN_DEBUG "%s: ecc 0x%04x ctrl 0x%04x "
                               "intr 0x%04x addr1 %#x addr8 %#x\n",
                               __func__, ecc, ctrl, interrupt, addr1, addr8);
                        return ONENAND_BBT_READ_ECC_ERROR;
                }
        } else {
                printk(KERN_ERR "%s: read timeout! ctrl 0x%04x "
                       "intr 0x%04x addr1 %#x addr8 %#x\n",
                       __func__, ctrl, interrupt, addr1, addr8);
                return ONENAND_BBT_READ_FATAL_ERROR;
        }

        /* Initial bad block case: 0x2400 or 0x0400 */
        if (ctrl & ONENAND_CTRL_ERROR) {
                printk(KERN_DEBUG "%s: ctrl 0x%04x intr 0x%04x addr1 %#x "
                       "addr8 %#x\n", __func__, ctrl, interrupt, addr1, addr8);
                return ONENAND_BBT_READ_ERROR;
        }

        return 0;
}

/**
 * onenand_bbt_read_oob - [MTD Interface] OneNAND read out-of-band for bbt scan
 * @param mtd           MTD device structure
 * @param from          offset to read from
 * @param ops           oob operation description structure
 *
 * OneNAND read out-of-band data from the spare area for bbt scan
 */
int onenand_bbt_read_oob(struct mtd_info *mtd, loff_t from, 
                            struct mtd_oob_ops *ops)
{
        struct onenand_chip *this = mtd->priv;
        int read = 0, thislen, column;
        int ret = 0, readcmd;
        size_t len = ops->ooblen;
        u_char *buf = ops->oobbuf;

        pr_debug("%s: from = 0x%08x, len = %zi\n", __func__, (unsigned int)from,
                        len);

        /* Initialize return value */
        ops->oobretlen = 0;

        /* Do not allow reads past end of device */
        if (unlikely((from + len) > mtd->size)) {
                printk(KERN_ERR "%s: Attempt read beyond end of device\n",
                        __func__);
                return ONENAND_BBT_READ_FATAL_ERROR;
        }

        /* Grab the lock and see if the device is available */
        onenand_get_device(mtd, FL_READING);

        column = from & (mtd->oobsize - 1);

        readcmd = ONENAND_IS_4KB_PAGE(this) ? ONENAND_CMD_READ : ONENAND_CMD_READOOB;

        while (read < len) {
                cond_resched();

                thislen = mtd->oobsize - column;
                thislen = min_t(int, thislen, len);

                this->command(mtd, readcmd, from, mtd->oobsize);

                onenand_update_bufferram(mtd, from, 0);

                ret = this->bbt_wait(mtd, FL_READING);
                if (unlikely(ret))
                        ret = onenand_recover_lsb(mtd, from, ret);

                if (ret)
                        break;

                this->read_bufferram(mtd, ONENAND_SPARERAM, buf, column, thislen);
                read += thislen;
                if (read == len)
                        break;

                buf += thislen;

                /* Read more? */
                if (read < len) {
                        /* Update Page size */
                        from += this->writesize;
                        column = 0;
                }
        }

        /* Deselect and wake up anyone waiting on the device */
        onenand_release_device(mtd);

        ops->oobretlen = read;
        return ret;
}

#ifdef CONFIG_MTD_ONENAND_VERIFY_WRITE
/**
 * onenand_verify_oob - [GENERIC] verify the oob contents after a write
 * @param mtd           MTD device structure
 * @param buf           the databuffer to verify
 * @param to            offset to read from
 */
static int onenand_verify_oob(struct mtd_info *mtd, const u_char *buf, loff_t to)
{
        struct onenand_chip *this = mtd->priv;
        u_char *oob_buf = this->oob_buf;
        int status, i, readcmd;

        readcmd = ONENAND_IS_4KB_PAGE(this) ? ONENAND_CMD_READ : ONENAND_CMD_READOOB;

        this->command(mtd, readcmd, to, mtd->oobsize);
        onenand_update_bufferram(mtd, to, 0);
        status = this->wait(mtd, FL_READING);
        if (status)
                return status;

        this->read_bufferram(mtd, ONENAND_SPARERAM, oob_buf, 0, mtd->oobsize);
        for (i = 0; i < mtd->oobsize; i++)
                if (buf[i] != 0xFF && buf[i] != oob_buf[i])
                        return -EBADMSG;

        return 0;
}

/**
 * onenand_verify - [GENERIC] verify the chip contents after a write
 * @param mtd          MTD device structure
 * @param buf          the databuffer to verify
 * @param addr         offset to read from
 * @param len          number of bytes to read and compare
 */
static int onenand_verify(struct mtd_info *mtd, const u_char *buf, loff_t addr, size_t len)
{
        struct onenand_chip *this = mtd->priv;
        int ret = 0;
        int thislen, column;

        column = addr & (this->writesize - 1);

        while (len != 0) {
                thislen = min_t(int, this->writesize - column, len);

                this->command(mtd, ONENAND_CMD_READ, addr, this->writesize);

                onenand_update_bufferram(mtd, addr, 0);

                ret = this->wait(mtd, FL_READING);
                if (ret)
                        return ret;

                onenand_update_bufferram(mtd, addr, 1);

                this->read_bufferram(mtd, ONENAND_DATARAM, this->verify_buf, 0, mtd->writesize);

                if (memcmp(buf, this->verify_buf + column, thislen))
                        return -EBADMSG;

                len -= thislen;
                buf += thislen;
                addr += thislen;
                column = 0;
        }

        return 0;
}
#else
#define onenand_verify(...)             (0)
#define onenand_verify_oob(...)         (0)
#endif

#define NOTALIGNED(x)   ((x & (this->subpagesize - 1)) != 0)

static void onenand_panic_wait(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;
        unsigned int interrupt;
        int i;
        
        for (i = 0; i < 2000; i++) {
                interrupt = this->read_word(this->base + ONENAND_REG_INTERRUPT);
                if (interrupt & ONENAND_INT_MASTER)
                        break;
                udelay(10);
        }
}

/**
 * onenand_panic_write - [MTD Interface] write buffer to FLASH in a panic context
 * @param mtd           MTD device structure
 * @param to            offset to write to
 * @param len           number of bytes to write
 * @param retlen        pointer to variable to store the number of written bytes
 * @param buf           the data to write
 *
 * Write with ECC
 */
static int onenand_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
                         size_t *retlen, const u_char *buf)
{
        struct onenand_chip *this = mtd->priv;
        int column, subpage;
        int written = 0;

        if (this->state == FL_PM_SUSPENDED)
                return -EBUSY;

        /* Wait for any existing operation to clear */
        onenand_panic_wait(mtd);

        pr_debug("%s: to = 0x%08x, len = %i\n", __func__, (unsigned int)to,
                        (int)len);

        /* Reject writes, which are not page aligned */
        if (unlikely(NOTALIGNED(to) || NOTALIGNED(len))) {
                printk(KERN_ERR "%s: Attempt to write not page aligned data\n",
                        __func__);
                return -EINVAL;
        }

        column = to & (mtd->writesize - 1);

        /* Loop until all data write */
        while (written < len) {
                int thislen = min_t(int, mtd->writesize - column, len - written);
                u_char *wbuf = (u_char *) buf;

                this->command(mtd, ONENAND_CMD_BUFFERRAM, to, thislen);

                /* Partial page write */
                subpage = thislen < mtd->writesize;
                if (subpage) {
                        memset(this->page_buf, 0xff, mtd->writesize);
                        memcpy(this->page_buf + column, buf, thislen);
                        wbuf = this->page_buf;
                }

                this->write_bufferram(mtd, ONENAND_DATARAM, wbuf, 0, mtd->writesize);
                this->write_bufferram(mtd, ONENAND_SPARERAM, ffchars, 0, mtd->oobsize);

                this->command(mtd, ONENAND_CMD_PROG, to, mtd->writesize);

                onenand_panic_wait(mtd);

                /* In partial page write we don't update bufferram */
                onenand_update_bufferram(mtd, to, !subpage);
                if (ONENAND_IS_2PLANE(this)) {
                        ONENAND_SET_BUFFERRAM1(this);
                        onenand_update_bufferram(mtd, to + this->writesize, !subpage);
                }

                written += thislen;

                if (written == len)
                        break;

                column = 0;
                to += thislen;
                buf += thislen;
        }

        *retlen = written;
        return 0;
}

/**
 * onenand_fill_auto_oob - [INTERN] oob auto-placement transfer
 * @param mtd           MTD device structure
 * @param oob_buf       oob buffer
 * @param buf           source address
 * @param column        oob offset to write to
 * @param thislen       oob length to write
 */
static int onenand_fill_auto_oob(struct mtd_info *mtd, u_char *oob_buf,
                                  const u_char *buf, int column, int thislen)
{
        return mtd_ooblayout_set_databytes(mtd, buf, oob_buf, column, thislen);
}

/**
 * onenand_write_ops_nolock - [OneNAND Interface] write main and/or out-of-band
 * @param mtd           MTD device structure
 * @param to            offset to write to
 * @param ops           oob operation description structure
 *
 * Write main and/or oob with ECC
 */
static int onenand_write_ops_nolock(struct mtd_info *mtd, loff_t to,
                                struct mtd_oob_ops *ops)
{
        struct onenand_chip *this = mtd->priv;
        int written = 0, column, thislen = 0, subpage = 0;
        int prev = 0, prevlen = 0, prev_subpage = 0, first = 1;
        int oobwritten = 0, oobcolumn, thisooblen, oobsize;
        size_t len = ops->len;
        size_t ooblen = ops->ooblen;
        const u_char *buf = ops->datbuf;
        const u_char *oob = ops->oobbuf;
        u_char *oobbuf;
        int ret = 0, cmd;

        pr_debug("%s: to = 0x%08x, len = %i\n", __func__, (unsigned int)to,
                        (int)len);

        /* Initialize retlen, in case of early exit */
        ops->retlen = 0;
        ops->oobretlen = 0;

        /* Reject writes, which are not page aligned */
        if (unlikely(NOTALIGNED(to) || NOTALIGNED(len))) {
                printk(KERN_ERR "%s: Attempt to write not page aligned data\n",
                        __func__);
                return -EINVAL;
        }

        /* Check zero length */
        if (!len)
                return 0;
        oobsize = mtd_oobavail(mtd, ops);
        oobcolumn = to & (mtd->oobsize - 1);

        column = to & (mtd->writesize - 1);

        /* Loop until all data write */
        while (1) {
                if (written < len) {
                        u_char *wbuf = (u_char *) buf;

                        thislen = min_t(int, mtd->writesize - column, len - written);
                        thisooblen = min_t(int, oobsize - oobcolumn, ooblen - oobwritten);

                        cond_resched();

                        this->command(mtd, ONENAND_CMD_BUFFERRAM, to, thislen);

                        /* Partial page write */
                        subpage = thislen < mtd->writesize;
                        if (subpage) {
                                memset(this->page_buf, 0xff, mtd->writesize);
                                memcpy(this->page_buf + column, buf, thislen);
                                wbuf = this->page_buf;
                        }

                        this->write_bufferram(mtd, ONENAND_DATARAM, wbuf, 0, mtd->writesize);

                        if (oob) {
                                oobbuf = this->oob_buf;

                                /* We send data to spare ram with oobsize
                                 * to prevent byte access */
                                memset(oobbuf, 0xff, mtd->oobsize);
                                if (ops->mode == MTD_OPS_AUTO_OOB)
                                        onenand_fill_auto_oob(mtd, oobbuf, oob, oobcolumn, thisooblen);
                                else
                                        memcpy(oobbuf + oobcolumn, oob, thisooblen);

                                oobwritten += thisooblen;
                                oob += thisooblen;
                                oobcolumn = 0;
                        } else
                                oobbuf = (u_char *) ffchars;

                        this->write_bufferram(mtd, ONENAND_SPARERAM, oobbuf, 0, mtd->oobsize);
                } else
                        ONENAND_SET_NEXT_BUFFERRAM(this);

                /*
                 * 2 PLANE, MLC, and Flex-OneNAND do not support
                 * write-while-program feature.
                 */
                if (!ONENAND_IS_2PLANE(this) && !ONENAND_IS_4KB_PAGE(this) && !first) {
                        ONENAND_SET_PREV_BUFFERRAM(this);

                        ret = this->wait(mtd, FL_WRITING);

                        /* In partial page write we don't update bufferram */
                        onenand_update_bufferram(mtd, prev, !ret && !prev_subpage);
                        if (ret) {
                                written -= prevlen;
                                printk(KERN_ERR "%s: write failed %d\n",
                                        __func__, ret);
                                break;
                        }

                        if (written == len) {
                                /* Only check verify write turn on */
                                ret = onenand_verify(mtd, buf - len, to - len, len);
                                if (ret)
                                        printk(KERN_ERR "%s: verify failed %d\n",
                                                __func__, ret);
                                break;
                        }

                        ONENAND_SET_NEXT_BUFFERRAM(this);
                }

                this->ongoing = 0;
                cmd = ONENAND_CMD_PROG;

                /* Exclude 1st OTP and OTP blocks for cache program feature */
                if (ONENAND_IS_CACHE_PROGRAM(this) &&
                    likely(onenand_block(this, to) != 0) &&
                    ONENAND_IS_4KB_PAGE(this) &&
                    ((written + thislen) < len)) {
                        cmd = ONENAND_CMD_2X_CACHE_PROG;
                        this->ongoing = 1;
                }

                this->command(mtd, cmd, to, mtd->writesize);

                /*
                 * 2 PLANE, MLC, and Flex-OneNAND wait here
                 */
                if (ONENAND_IS_2PLANE(this) || ONENAND_IS_4KB_PAGE(this)) {
                        ret = this->wait(mtd, FL_WRITING);

                        /* In partial page write we don't update bufferram */
                        onenand_update_bufferram(mtd, to, !ret && !subpage);
                        if (ret) {
                                printk(KERN_ERR "%s: write failed %d\n",
                                        __func__, ret);
                                break;
                        }

                        /* Only check verify write turn on */
                        ret = onenand_verify(mtd, buf, to, thislen);
                        if (ret) {
                                printk(KERN_ERR "%s: verify failed %d\n",
                                        __func__, ret);
                                break;
                        }

                        written += thislen;

                        if (written == len)
                                break;

                } else
                        written += thislen;

                column = 0;
                prev_subpage = subpage;
                prev = to;
                prevlen = thislen;
                to += thislen;
                buf += thislen;
                first = 0;
        }

        /* In error case, clear all bufferrams */
        if (written != len)
                onenand_invalidate_bufferram(mtd, 0, -1);

        ops->retlen = written;
        ops->oobretlen = oobwritten;

        return ret;
}


/**
 * onenand_write_oob_nolock - [INTERN] OneNAND write out-of-band
 * @param mtd           MTD device structure
 * @param to            offset to write to
 * @param len           number of bytes to write
 * @param retlen        pointer to variable to store the number of written bytes
 * @param buf           the data to write
 * @param mode          operation mode
 *
 * OneNAND write out-of-band
 */
static int onenand_write_oob_nolock(struct mtd_info *mtd, loff_t to,
                                    struct mtd_oob_ops *ops)
{
        struct onenand_chip *this = mtd->priv;
        int column, ret = 0, oobsize;
        int written = 0, oobcmd;
        u_char *oobbuf;
        size_t len = ops->ooblen;
        const u_char *buf = ops->oobbuf;
        unsigned int mode = ops->mode;

        to += ops->ooboffs;

        pr_debug("%s: to = 0x%08x, len = %i\n", __func__, (unsigned int)to,
                        (int)len);

        /* Initialize retlen, in case of early exit */
        ops->oobretlen = 0;

        if (mode == MTD_OPS_AUTO_OOB)
                oobsize = mtd->oobavail;
        else
                oobsize = mtd->oobsize;

        column = to & (mtd->oobsize - 1);

        if (unlikely(column >= oobsize)) {
                printk(KERN_ERR "%s: Attempted to start write outside oob\n",
                        __func__);
                return -EINVAL;
        }

        /* For compatibility with NAND: Do not allow write past end of page */
        if (unlikely(column + len > oobsize)) {
                printk(KERN_ERR "%s: Attempt to write past end of page\n",
                        __func__);
                return -EINVAL;
        }

        oobbuf = this->oob_buf;

        oobcmd = ONENAND_IS_4KB_PAGE(this) ? ONENAND_CMD_PROG : ONENAND_CMD_PROGOOB;

        /* Loop until all data write */
        while (written < len) {
                int thislen = min_t(int, oobsize, len - written);

                cond_resched();

                this->command(mtd, ONENAND_CMD_BUFFERRAM, to, mtd->oobsize);

                /* We send data to spare ram with oobsize
                 * to prevent byte access */
                memset(oobbuf, 0xff, mtd->oobsize);
                if (mode == MTD_OPS_AUTO_OOB)
                        onenand_fill_auto_oob(mtd, oobbuf, buf, column, thislen);
                else
                        memcpy(oobbuf + column, buf, thislen);
                this->write_bufferram(mtd, ONENAND_SPARERAM, oobbuf, 0, mtd->oobsize);

                if (ONENAND_IS_4KB_PAGE(this)) {
                        /* Set main area of DataRAM to 0xff*/
                        memset(this->page_buf, 0xff, mtd->writesize);
                        this->write_bufferram(mtd, ONENAND_DATARAM,
                                         this->page_buf, 0, mtd->writesize);
                }

                this->command(mtd, oobcmd, to, mtd->oobsize);

                onenand_update_bufferram(mtd, to, 0);
                if (ONENAND_IS_2PLANE(this)) {
                        ONENAND_SET_BUFFERRAM1(this);
                        onenand_update_bufferram(mtd, to + this->writesize, 0);
                }

                ret = this->wait(mtd, FL_WRITING);
                if (ret) {
                        printk(KERN_ERR "%s: write failed %d\n", __func__, ret);
                        break;
                }

                ret = onenand_verify_oob(mtd, oobbuf, to);
                if (ret) {
                        printk(KERN_ERR "%s: verify failed %d\n",
                                __func__, ret);
                        break;
                }

                written += thislen;
                if (written == len)
                        break;

                to += mtd->writesize;
                buf += thislen;
                column = 0;
        }

        ops->oobretlen = written;

        return ret;
}

/**
 * onenand_write_oob - [MTD Interface] NAND write data and/or out-of-band
 * @param mtd:          MTD device structure
 * @param to:           offset to write
 * @param ops:          oob operation description structure
 */
static int onenand_write_oob(struct mtd_info *mtd, loff_t to,
                             struct mtd_oob_ops *ops)
{
        int ret;

        switch (ops->mode) {
        case MTD_OPS_PLACE_OOB:
        case MTD_OPS_AUTO_OOB:
                break;
        case MTD_OPS_RAW:
                /* Not implemented yet */
        default:
                return -EINVAL;
        }

        onenand_get_device(mtd, FL_WRITING);
        if (ops->datbuf)
                ret = onenand_write_ops_nolock(mtd, to, ops);
        else
                ret = onenand_write_oob_nolock(mtd, to, ops);
        onenand_release_device(mtd);

        return ret;
}

/**
 * onenand_block_isbad_nolock - [GENERIC] Check if a block is marked bad
 * @param mtd           MTD device structure
 * @param ofs           offset from device start
 * @param allowbbt      1, if its allowed to access the bbt area
 *
 * Check, if the block is bad. Either by reading the bad block table or
 * calling of the scan function.
 */
static int onenand_block_isbad_nolock(struct mtd_info *mtd, loff_t ofs, int allowbbt)
{
        struct onenand_chip *this = mtd->priv;
        struct bbm_info *bbm = this->bbm;

        /* Return info from the table */
        return bbm->isbad_bbt(mtd, ofs, allowbbt);
}


static int onenand_multiblock_erase_verify(struct mtd_info *mtd,
                                           struct erase_info *instr)
{
        struct onenand_chip *this = mtd->priv;
        loff_t addr = instr->addr;
        int len = instr->len;
        unsigned int block_size = (1 << this->erase_shift);
        int ret = 0;

        while (len) {
                this->command(mtd, ONENAND_CMD_ERASE_VERIFY, addr, block_size);
                ret = this->wait(mtd, FL_VERIFYING_ERASE);
                if (ret) {
                        printk(KERN_ERR "%s: Failed verify, block %d\n",
                               __func__, onenand_block(this, addr));
                        instr->fail_addr = addr;
                        return -1;
                }
                len -= block_size;
                addr += block_size;
        }
        return 0;
}

/**
 * onenand_multiblock_erase - [INTERN] erase block(s) using multiblock erase
 * @param mtd           MTD device structure
 * @param instr         erase instruction
 * @param region        erase region
 *
 * Erase one or more blocks up to 64 block at a time
 */
static int onenand_multiblock_erase(struct mtd_info *mtd,
                                    struct erase_info *instr,
                                    unsigned int block_size)
{
        struct onenand_chip *this = mtd->priv;
        loff_t addr = instr->addr;
        int len = instr->len;
        int eb_count = 0;
        int ret = 0;
        int bdry_block = 0;

        if (ONENAND_IS_DDP(this)) {
                loff_t bdry_addr = this->chipsize >> 1;
                if (addr < bdry_addr && (addr + len) > bdry_addr)
                        bdry_block = bdry_addr >> this->erase_shift;
        }

        /* Pre-check bbs */
        while (len) {
                /* Check if we have a bad block, we do not erase bad blocks */
                if (onenand_block_isbad_nolock(mtd, addr, 0)) {
                        printk(KERN_WARNING "%s: attempt to erase a bad block "
                               "at addr 0x%012llx\n",
                               __func__, (unsigned long long) addr);
                        return -EIO;
                }
                len -= block_size;
                addr += block_size;
        }

        len = instr->len;
        addr = instr->addr;

        /* loop over 64 eb batches */
        while (len) {
                struct erase_info verify_instr = *instr;
                int max_eb_count = MB_ERASE_MAX_BLK_COUNT;

                verify_instr.addr = addr;
                verify_instr.len = 0;

                /* do not cross chip boundary */
                if (bdry_block) {
                        int this_block = (addr >> this->erase_shift);

                        if (this_block < bdry_block) {
                                max_eb_count = min(max_eb_count,
                                                   (bdry_block - this_block));
                        }
                }

                eb_count = 0;

                while (len > block_size && eb_count < (max_eb_count - 1)) {
                        this->command(mtd, ONENAND_CMD_MULTIBLOCK_ERASE,
                                      addr, block_size);
                        onenand_invalidate_bufferram(mtd, addr, block_size);

                        ret = this->wait(mtd, FL_PREPARING_ERASE);
                        if (ret) {
                                printk(KERN_ERR "%s: Failed multiblock erase, "
                                       "block %d\n", __func__,
                                       onenand_block(this, addr));
                                instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
                                return -EIO;
                        }

                        len -= block_size;
                        addr += block_size;
                        eb_count++;
                }

                /* last block of 64-eb series */
                cond_resched();
                this->command(mtd, ONENAND_CMD_ERASE, addr, block_size);
                onenand_invalidate_bufferram(mtd, addr, block_size);

                ret = this->wait(mtd, FL_ERASING);
                /* Check if it is write protected */
                if (ret) {
                        printk(KERN_ERR "%s: Failed erase, block %d\n",
                               __func__, onenand_block(this, addr));
                        instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
                        return -EIO;
                }

                len -= block_size;
                addr += block_size;
                eb_count++;

                /* verify */
                verify_instr.len = eb_count * block_size;
                if (onenand_multiblock_erase_verify(mtd, &verify_instr)) {
                        instr->fail_addr = verify_instr.fail_addr;
                        return -EIO;
                }

        }
        return 0;
}


/**
 * onenand_block_by_block_erase - [INTERN] erase block(s) using regular erase
 * @param mtd           MTD device structure
 * @param instr         erase instruction
 * @param region        erase region
 * @param block_size    erase block size
 *
 * Erase one or more blocks one block at a time
 */
static int onenand_block_by_block_erase(struct mtd_info *mtd,
                                        struct erase_info *instr,
                                        struct mtd_erase_region_info *region,
                                        unsigned int block_size)
{
        struct onenand_chip *this = mtd->priv;
        loff_t addr = instr->addr;
        int len = instr->len;
        loff_t region_end = 0;
        int ret = 0;

        if (region) {
                /* region is set for Flex-OneNAND */
                region_end = region->offset + region->erasesize * region->numblocks;
        }

        /* Loop through the blocks */
        while (len) {
                cond_resched();

                /* Check if we have a bad block, we do not erase bad blocks */
                if (onenand_block_isbad_nolock(mtd, addr, 0)) {
                        printk(KERN_WARNING "%s: attempt to erase a bad block "
                                        "at addr 0x%012llx\n",
                                        __func__, (unsigned long long) addr);
                        return -EIO;
                }

                this->command(mtd, ONENAND_CMD_ERASE, addr, block_size);

                onenand_invalidate_bufferram(mtd, addr, block_size);

                ret = this->wait(mtd, FL_ERASING);
                /* Check, if it is write protected */
                if (ret) {
                        printk(KERN_ERR "%s: Failed erase, block %d\n",
                                __func__, onenand_block(this, addr));
                        instr->fail_addr = addr;
                        return -EIO;
                }

                len -= block_size;
                addr += block_size;

                if (region && addr == region_end) {
                        if (!len)
                                break;
                        region++;

                        block_size = region->erasesize;
                        region_end = region->offset + region->erasesize * region->numblocks;

                        if (len & (block_size - 1)) {
                                /* FIXME: This should be handled at MTD partitioning level. */
                                printk(KERN_ERR "%s: Unaligned address\n",
                                        __func__);
                                return -EIO;
                        }
                }
        }
        return 0;
}

/**
 * onenand_erase - [MTD Interface] erase block(s)
 * @param mtd           MTD device structure
 * @param instr         erase instruction
 *
 * Erase one or more blocks
 */
static int onenand_erase(struct mtd_info *mtd, struct erase_info *instr)
{
        struct onenand_chip *this = mtd->priv;
        unsigned int block_size;
        loff_t addr = instr->addr;
        loff_t len = instr->len;
        int ret = 0;
        struct mtd_erase_region_info *region = NULL;
        loff_t region_offset = 0;

        pr_debug("%s: start=0x%012llx, len=%llu\n", __func__,
                        (unsigned long long)instr->addr,
                        (unsigned long long)instr->len);

        if (FLEXONENAND(this)) {
                /* Find the eraseregion of this address */
                int i = flexonenand_region(mtd, addr);

                region = &mtd->eraseregions[i];
                block_size = region->erasesize;

                /* Start address within region must align on block boundary.
                 * Erase region's start offset is always block start address.
                 */
                region_offset = region->offset;
        } else
                block_size = 1 << this->erase_shift;

        /* Start address must align on block boundary */
        if (unlikely((addr - region_offset) & (block_size - 1))) {
                printk(KERN_ERR "%s: Unaligned address\n", __func__);
                return -EINVAL;
        }

        /* Length must align on block boundary */
        if (unlikely(len & (block_size - 1))) {
                printk(KERN_ERR "%s: Length not block aligned\n", __func__);
                return -EINVAL;
        }

        /* Grab the lock and see if the device is available */
        onenand_get_device(mtd, FL_ERASING);

        if (ONENAND_IS_4KB_PAGE(this) || region ||
            instr->len < MB_ERASE_MIN_BLK_COUNT * block_size) {
                /* region is set for Flex-OneNAND (no mb erase) */
                ret = onenand_block_by_block_erase(mtd, instr,
                                                   region, block_size);
        } else {
                ret = onenand_multiblock_erase(mtd, instr, block_size);
        }

        /* Deselect and wake up anyone waiting on the device */
        onenand_release_device(mtd);

        return ret;
}

/**
 * onenand_sync - [MTD Interface] sync
 * @param mtd           MTD device structure
 *
 * Sync is actually a wait for chip ready function
 */
static void onenand_sync(struct mtd_info *mtd)
{
        pr_debug("%s: called\n", __func__);

        /* Grab the lock and see if the device is available */
        onenand_get_device(mtd, FL_SYNCING);

        /* Release it and go back */
        onenand_release_device(mtd);
}

/**
 * onenand_block_isbad - [MTD Interface] Check whether the block at the given offset is bad
 * @param mtd           MTD device structure
 * @param ofs           offset relative to mtd start
 *
 * Check whether the block is bad
 */
static int onenand_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
        int ret;

        onenand_get_device(mtd, FL_READING);
        ret = onenand_block_isbad_nolock(mtd, ofs, 0);
        onenand_release_device(mtd);
        return ret;
}

/**
 * onenand_default_block_markbad - [DEFAULT] mark a block bad
 * @param mtd           MTD device structure
 * @param ofs           offset from device start
 *
 * This is the default implementation, which can be overridden by
 * a hardware specific driver.
 */
static int onenand_default_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
        struct onenand_chip *this = mtd->priv;
        struct bbm_info *bbm = this->bbm;
        u_char buf[2] = {0, 0};
        struct mtd_oob_ops ops = {
                .mode = MTD_OPS_PLACE_OOB,
                .ooblen = 2,
                .oobbuf = buf,
                .ooboffs = 0,
        };
        int block;

        /* Get block number */
        block = onenand_block(this, ofs);
        if (bbm->bbt)
                bbm->bbt[block >> 2] |= 0x01 << ((block & 0x03) << 1);

        /* We write two bytes, so we don't have to mess with 16-bit access */
        ofs += mtd->oobsize + (bbm->badblockpos & ~0x01);
        /* FIXME : What to do when marking SLC block in partition
         *         with MLC erasesize? For now, it is not advisable to
         *         create partitions containing both SLC and MLC regions.
         */
        return onenand_write_oob_nolock(mtd, ofs, &ops);
}

/**
 * onenand_block_markbad - [MTD Interface] Mark the block at the given offset as bad
 * @param mtd           MTD device structure
 * @param ofs           offset relative to mtd start
 *
 * Mark the block as bad
 */
static int onenand_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
        struct onenand_chip *this = mtd->priv;
        int ret;

        ret = onenand_block_isbad(mtd, ofs);
        if (ret) {
                /* If it was bad already, return success and do nothing */
                if (ret > 0)
                        return 0;
                return ret;
        }

        onenand_get_device(mtd, FL_WRITING);
        ret = this->block_markbad(mtd, ofs);
        onenand_release_device(mtd);
        return ret;
}

/**
 * onenand_do_lock_cmd - [OneNAND Interface] Lock or unlock block(s)
 * @param mtd           MTD device structure
 * @param ofs           offset relative to mtd start
 * @param len           number of bytes to lock or unlock
 * @param cmd           lock or unlock command
 *
 * Lock or unlock one or more blocks
 */
static int onenand_do_lock_cmd(struct mtd_info *mtd, loff_t ofs, size_t len, int cmd)
{
        struct onenand_chip *this = mtd->priv;
        int start, end, block, value, status;
        int wp_status_mask;

        start = onenand_block(this, ofs);
        end = onenand_block(this, ofs + len) - 1;

        if (cmd == ONENAND_CMD_LOCK)
                wp_status_mask = ONENAND_WP_LS;
        else
                wp_status_mask = ONENAND_WP_US;

        /* Continuous lock scheme */
        if (this->options & ONENAND_HAS_CONT_LOCK) {
                /* Set start block address */
                this->write_word(start, this->base + ONENAND_REG_START_BLOCK_ADDRESS);
                /* Set end block address */
                this->write_word(end, this->base +  ONENAND_REG_END_BLOCK_ADDRESS);
                /* Write lock command */
                this->command(mtd, cmd, 0, 0);

                /* There's no return value */
                this->wait(mtd, FL_LOCKING);

                /* Sanity check */
                while (this->read_word(this->base + ONENAND_REG_CTRL_STATUS)
                    & ONENAND_CTRL_ONGO)
                        continue;

                /* Check lock status */
                status = this->read_word(this->base + ONENAND_REG_WP_STATUS);
                if (!(status & wp_status_mask))
                        printk(KERN_ERR "%s: wp status = 0x%x\n",
                                __func__, status);

                return 0;
        }

        /* Block lock scheme */
        for (block = start; block < end + 1; block++) {
                /* Set block address */
                value = onenand_block_address(this, block);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS1);
                /* Select DataRAM for DDP */
                value = onenand_bufferram_address(this, block);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS2);
                /* Set start block address */
                this->write_word(block, this->base + ONENAND_REG_START_BLOCK_ADDRESS);
                /* Write lock command */
                this->command(mtd, cmd, 0, 0);

                /* There's no return value */
                this->wait(mtd, FL_LOCKING);

                /* Sanity check */
                while (this->read_word(this->base + ONENAND_REG_CTRL_STATUS)
                    & ONENAND_CTRL_ONGO)
                        continue;

                /* Check lock status */
                status = this->read_word(this->base + ONENAND_REG_WP_STATUS);
                if (!(status & wp_status_mask))
                        printk(KERN_ERR "%s: block = %d, wp status = 0x%x\n",
                                __func__, block, status);
        }

        return 0;
}

/**
 * onenand_lock - [MTD Interface] Lock block(s)
 * @param mtd           MTD device structure
 * @param ofs           offset relative to mtd start
 * @param len           number of bytes to unlock
 *
 * Lock one or more blocks
 */
static int onenand_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        int ret;

        onenand_get_device(mtd, FL_LOCKING);
        ret = onenand_do_lock_cmd(mtd, ofs, len, ONENAND_CMD_LOCK);
        onenand_release_device(mtd);
        return ret;
}

/**
 * onenand_unlock - [MTD Interface] Unlock block(s)
 * @param mtd           MTD device structure
 * @param ofs           offset relative to mtd start
 * @param len           number of bytes to unlock
 *
 * Unlock one or more blocks
 */
static int onenand_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
        int ret;

        onenand_get_device(mtd, FL_LOCKING);
        ret = onenand_do_lock_cmd(mtd, ofs, len, ONENAND_CMD_UNLOCK);
        onenand_release_device(mtd);
        return ret;
}

/**
 * onenand_check_lock_status - [OneNAND Interface] Check lock status
 * @param this          onenand chip data structure
 *
 * Check lock status
 */
static int onenand_check_lock_status(struct onenand_chip *this)
{
        unsigned int value, block, status;
        unsigned int end;

        end = this->chipsize >> this->erase_shift;
        for (block = 0; block < end; block++) {
                /* Set block address */
                value = onenand_block_address(this, block);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS1);
                /* Select DataRAM for DDP */
                value = onenand_bufferram_address(this, block);
                this->write_word(value, this->base + ONENAND_REG_START_ADDRESS2);
                /* Set start block address */
                this->write_word(block, this->base + ONENAND_REG_START_BLOCK_ADDRESS);

                /* Check lock status */
                status = this->read_word(this->base + ONENAND_REG_WP_STATUS);
                if (!(status & ONENAND_WP_US)) {
                        printk(KERN_ERR "%s: block = %d, wp status = 0x%x\n",
                                __func__, block, status);
                        return 0;
                }
        }

        return 1;
}

/**
 * onenand_unlock_all - [OneNAND Interface] unlock all blocks
 * @param mtd           MTD device structure
 *
 * Unlock all blocks
 */
static void onenand_unlock_all(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;
        loff_t ofs = 0;
        loff_t len = mtd->size;

        if (this->options & ONENAND_HAS_UNLOCK_ALL) {
                /* Set start block address */
                this->write_word(0, this->base + ONENAND_REG_START_BLOCK_ADDRESS);
                /* Write unlock command */
                this->command(mtd, ONENAND_CMD_UNLOCK_ALL, 0, 0);

                /* There's no return value */
                this->wait(mtd, FL_LOCKING);

                /* Sanity check */
                while (this->read_word(this->base + ONENAND_REG_CTRL_STATUS)
                    & ONENAND_CTRL_ONGO)
                        continue;

                /* Don't check lock status */
                if (this->options & ONENAND_SKIP_UNLOCK_CHECK)
                        return;

                /* Check lock status */
                if (onenand_check_lock_status(this))
                        return;

                /* Workaround for all block unlock in DDP */
                if (ONENAND_IS_DDP(this) && !FLEXONENAND(this)) {
                        /* All blocks on another chip */
                        ofs = this->chipsize >> 1;
                        len = this->chipsize >> 1;
                }
        }

        onenand_do_lock_cmd(mtd, ofs, len, ONENAND_CMD_UNLOCK);
}

#ifdef CONFIG_MTD_ONENAND_OTP

/**
 * onenand_otp_command - Send OTP specific command to OneNAND device
 * @param mtd    MTD device structure
 * @param cmd    the command to be sent
 * @param addr   offset to read from or write to
 * @param len    number of bytes to read or write
 */
static int onenand_otp_command(struct mtd_info *mtd, int cmd, loff_t addr,
                                size_t len)
{
        struct onenand_chip *this = mtd->priv;
        int value, block, page;

        /* Address translation */
        switch (cmd) {
        case ONENAND_CMD_OTP_ACCESS:
                block = (int) (addr >> this->erase_shift);
                page = -1;
                break;

        default:
                block = (int) (addr >> this->erase_shift);
                page = (int) (addr >> this->page_shift);

                if (ONENAND_IS_2PLANE(this)) {
                        /* Make the even block number */
                        block &= ~1;
                        /* Is it the odd plane? */
                        if (addr & this->writesize)
                                block++;
                        page >>= 1;
                }
                page &= this->page_mask;
                break;
        }

        if (block != -1) {
                /* Write 'DFS, FBA' of Flash */
                value = onenand_block_address(this, block);
                this->write_word(value, this->base +
                                ONENAND_REG_START_ADDRESS1);
        }

        if (page != -1) {
                /* Now we use page size operation */
                int sectors = 4, count = 4;
                int dataram;

                switch (cmd) {
                default:
                        if (ONENAND_IS_2PLANE(this) && cmd == ONENAND_CMD_PROG)
                                cmd = ONENAND_CMD_2X_PROG;
                        dataram = ONENAND_CURRENT_BUFFERRAM(this);
                        break;
                }

                /* Write 'FPA, FSA' of Flash */
                value = onenand_page_address(page, sectors);
                this->write_word(value, this->base +
                                ONENAND_REG_START_ADDRESS8);

                /* Write 'BSA, BSC' of DataRAM */
                value = onenand_buffer_address(dataram, sectors, count);
                this->write_word(value, this->base + ONENAND_REG_START_BUFFER);
        }

        /* Interrupt clear */
        this->write_word(ONENAND_INT_CLEAR, this->base + ONENAND_REG_INTERRUPT);

        /* Write command */
        this->write_word(cmd, this->base + ONENAND_REG_COMMAND);

        return 0;
}

/**
 * onenand_otp_write_oob_nolock - [INTERN] OneNAND write out-of-band, specific to OTP
 * @param mtd           MTD device structure
 * @param to            offset to write to
 * @param len           number of bytes to write
 * @param retlen        pointer to variable to store the number of written bytes
 * @param buf           the data to write
 *
 * OneNAND write out-of-band only for OTP
 */
static int onenand_otp_write_oob_nolock(struct mtd_info *mtd, loff_t to,
                                    struct mtd_oob_ops *ops)
{
        struct onenand_chip *this = mtd->priv;
        int column, ret = 0, oobsize;
        int written = 0;
        u_char *oobbuf;
        size_t len = ops->ooblen;
        const u_char *buf = ops->oobbuf;
        int block, value, status;

        to += ops->ooboffs;

        /* Initialize retlen, in case of early exit */
        ops->oobretlen = 0;

        oobsize = mtd->oobsize;

        column = to & (mtd->oobsize - 1);

        oobbuf = this->oob_buf;

        /* Loop until all data write */
        while (written < len) {
                int thislen = min_t(int, oobsize, len - written);

                cond_resched();

                block = (int) (to >> this->erase_shift);
                /*
                 * Write 'DFS, FBA' of Flash
                 * Add: F100h DQ=DFS, FBA
                 */

                value = onenand_block_address(this, block);
                this->write_word(value, this->base +
                                ONENAND_REG_START_ADDRESS1);

                /*
                 * Select DataRAM for DDP
                 * Add: F101h DQ=DBS
                 */

                value = onenand_bufferram_address(this, block);
                this->write_word(value, this->base +
                                ONENAND_REG_START_ADDRESS2);
                ONENAND_SET_NEXT_BUFFERRAM(this);

                /*
                 * Enter OTP access mode
                 */
                this->command(mtd, ONENAND_CMD_OTP_ACCESS, 0, 0);
                this->wait(mtd, FL_OTPING);

                /* We send data to spare ram with oobsize
                 * to prevent byte access */
                memcpy(oobbuf + column, buf, thislen);

                /*
                 * Write Data into DataRAM
                 * Add: 8th Word
                 * in sector0/spare/page0
                 * DQ=XXFCh
                 */
                this->write_bufferram(mtd, ONENAND_SPARERAM,
                                        oobbuf, 0, mtd->oobsize);

                onenand_otp_command(mtd, ONENAND_CMD_PROGOOB, to, mtd->oobsize);
                onenand_update_bufferram(mtd, to, 0);
                if (ONENAND_IS_2PLANE(this)) {
                        ONENAND_SET_BUFFERRAM1(this);
                        onenand_update_bufferram(mtd, to + this->writesize, 0);
                }

                ret = this->wait(mtd, FL_WRITING);
                if (ret) {
                        printk(KERN_ERR "%s: write failed %d\n", __func__, ret);
                        break;
                }

                /* Exit OTP access mode */
                this->command(mtd, ONENAND_CMD_RESET, 0, 0);
                this->wait(mtd, FL_RESETING);

                status = this->read_word(this->base + ONENAND_REG_CTRL_STATUS);
                status &= 0x60;

                if (status == 0x60) {
                        printk(KERN_DEBUG "\nBLOCK\tSTATUS\n");
                        printk(KERN_DEBUG "1st Block\tLOCKED\n");
                        printk(KERN_DEBUG "OTP Block\tLOCKED\n");
                } else if (status == 0x20) {
                        printk(KERN_DEBUG "\nBLOCK\tSTATUS\n");
                        printk(KERN_DEBUG "1st Block\tLOCKED\n");
                        printk(KERN_DEBUG "OTP Block\tUN-LOCKED\n");
                } else if (status == 0x40) {
                        printk(KERN_DEBUG "\nBLOCK\tSTATUS\n");
                        printk(KERN_DEBUG "1st Block\tUN-LOCKED\n");
                        printk(KERN_DEBUG "OTP Block\tLOCKED\n");
                } else {
                        printk(KERN_DEBUG "Reboot to check\n");
                }

                written += thislen;
                if (written == len)
                        break;

                to += mtd->writesize;
                buf += thislen;
                column = 0;
        }

        ops->oobretlen = written;

        return ret;
}

/* Internal OTP operation */
typedef int (*otp_op_t)(struct mtd_info *mtd, loff_t form, size_t len,
                size_t *retlen, u_char *buf);

/**
 * do_otp_read - [DEFAULT] Read OTP block area
 * @param mtd           MTD device structure
 * @param from          The offset to read
 * @param len           number of bytes to read
 * @param retlen        pointer to variable to store the number of readbytes
 * @param buf           the databuffer to put/get data
 *
 * Read OTP block area.
 */
static int do_otp_read(struct mtd_info *mtd, loff_t from, size_t len,
                size_t *retlen, u_char *buf)
{
        struct onenand_chip *this = mtd->priv;
        struct mtd_oob_ops ops = {
                .len    = len,
                .ooblen = 0,
                .datbuf = buf,
                .oobbuf = NULL,
        };
        int ret;

        /* Enter OTP access mode */
        this->command(mtd, ONENAND_CMD_OTP_ACCESS, 0, 0);
        this->wait(mtd, FL_OTPING);

        ret = ONENAND_IS_4KB_PAGE(this) ?
                onenand_mlc_read_ops_nolock(mtd, from, &ops) :
                onenand_read_ops_nolock(mtd, from, &ops);

        /* Exit OTP access mode */
        this->command(mtd, ONENAND_CMD_RESET, 0, 0);
        this->wait(mtd, FL_RESETING);

        return ret;
}

/**
 * do_otp_write - [DEFAULT] Write OTP block area
 * @param mtd           MTD device structure
 * @param to            The offset to write
 * @param len           number of bytes to write
 * @param retlen        pointer to variable to store the number of write bytes
 * @param buf           the databuffer to put/get data
 *
 * Write OTP block area.
 */
static int do_otp_write(struct mtd_info *mtd, loff_t to, size_t len,
                size_t *retlen, u_char *buf)
{
        struct onenand_chip *this = mtd->priv;
        unsigned char *pbuf = buf;
        int ret;
        struct mtd_oob_ops ops;

        /* Force buffer page aligned */
        if (len < mtd->writesize) {
                memcpy(this->page_buf, buf, len);
                memset(this->page_buf + len, 0xff, mtd->writesize - len);
                pbuf = this->page_buf;
                len = mtd->writesize;
        }

        /* Enter OTP access mode */
        this->command(mtd, ONENAND_CMD_OTP_ACCESS, 0, 0);
        this->wait(mtd, FL_OTPING);

        ops.len = len;
        ops.ooblen = 0;
        ops.datbuf = pbuf;
        ops.oobbuf = NULL;
        ret = onenand_write_ops_nolock(mtd, to, &ops);
        *retlen = ops.retlen;

        /* Exit OTP access mode */
        this->command(mtd, ONENAND_CMD_RESET, 0, 0);
        this->wait(mtd, FL_RESETING);

        return ret;
}

/**
 * do_otp_lock - [DEFAULT] Lock OTP block area
 * @param mtd           MTD device structure
 * @param from          The offset to lock
 * @param len           number of bytes to lock
 * @param retlen        pointer to variable to store the number of lock bytes
 * @param buf           the databuffer to put/get data
 *
 * Lock OTP block area.
 */
static int do_otp_lock(struct mtd_info *mtd, loff_t from, size_t len,
                size_t *retlen, u_char *buf)
{
        struct onenand_chip *this = mtd->priv;
        struct mtd_oob_ops ops;
        int ret;

        if (FLEXONENAND(this)) {

                /* Enter OTP access mode */
                this->command(mtd, ONENAND_CMD_OTP_ACCESS, 0, 0);
                this->wait(mtd, FL_OTPING);