[MTD] OneNAND: fix onenand_wait bug in read ecc error

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / mtd / onenand / onenand_base.c

/*
 *  linux/drivers/mtd/onenand/onenand_base.c
 *
 *  Copyright (C) 2005-2006 Samsung Electronics
 *  Kyungmin Park <kyungmin.park@samsung.com>
 *
 * 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/init.h>
#include <linux/sched.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>

/**
 * onenand_oob_64 - oob info for large (2KB) page
 */
static struct nand_ecclayout onenand_oob_64 = {
        .eccbytes       = 20,
        .eccpos         = {
                8, 9, 10, 11, 12,
                24, 25, 26, 27, 28,
                40, 41, 42, 43, 44,
                56, 57, 58, 59, 60,
                },
        .oobfree        = {
                {2, 3}, {14, 2}, {18, 3}, {30, 2},
                {34, 3}, {46, 2}, {50, 3}, {62, 2}
        }
};

/**
 * onenand_oob_32 - oob info for middle (1KB) page
 */
static struct nand_ecclayout onenand_oob_32 = {
        .eccbytes       = 10,
        .eccpos         = {
                8, 9, 10, 11, 12,
                24, 25, 26, 27, 28,
                },
        .oobfree        = { {2, 3}, {14, 2}, {18, 3}, {30, 2} }
};

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 */
};

/**
 * 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)
{
        if (this->device_id & ONENAND_DEVICE_IS_DDP) {
                /* Device Flash Core select, NAND Flash Block Address */
                int dfs = 0;

                if (block & this->density_mask)
                        dfs = 1;

                return (dfs << ONENAND_DDP_SHIFT) |
                        (block & (this->density_mask - 1));
        }

        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)
{
        if (this->device_id & ONENAND_DEVICE_IS_DDP) {
                /* Device BufferRAM Select */
                int dbs = 0;

                if (block & this->density_mask)
                        dbs = 1;

                return (dbs << ONENAND_DDP_SHIFT);
        }

        return 0;
}

/**
 * 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);
}

/**
 * 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, readcmd = 0, block_cmd = 0;
        int 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 ONENAND_CMD_ERASE:
        case ONENAND_CMD_BUFFERRAM:
        case ONENAND_CMD_OTP_ACCESS:
                block_cmd = 1;
                block = (int) (addr >> this->erase_shift);
                page = -1;
                break;

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

                /* 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);

                if (block_cmd) {
                        /* 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 = 4, count = 4;
                int dataram;

                switch (cmd) {
                case ONENAND_CMD_READ:
                case ONENAND_CMD_READOOB:
                        dataram = ONENAND_SET_NEXT_BUFFERRAM(this);
                        readcmd = 1;
                        break;

                default:
                        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);

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

        /* 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_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)
                        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);

        if (ctrl & ONENAND_CTRL_ERROR) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_wait: controller error = 0x%04x\n", ctrl);
                if (ctrl & ONENAND_CTRL_LOCK)
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_wait: it's locked error.\n");
                return ctrl;
        }

        if (interrupt & ONENAND_INT_READ) {
                int ecc = this->read_word(this->base + ONENAND_REG_ECC_STATUS);
                if (ecc) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_wait: ECC error = 0x%04x\n", ecc);
                        if (ecc & ONENAND_ECC_2BIT_ALL)
                                mtd->ecc_stats.failed++;
                        else if (ecc & ONENAND_ECC_1BIT_ALL)
                                mtd->ecc_stats.corrected++;
                }
                return ecc;
        }

        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 = (struct onenand_chip *) 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)) {
                if (area == ONENAND_DATARAM)
                        return mtd->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_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 block, page;
        int i;

        block = (int) (addr >> this->erase_shift);
        page = (int) (addr >> this->page_shift);
        page &= this->page_mask;

        i = ONENAND_CURRENT_BUFFERRAM(this);

        /* Is there valid data? */
        if (this->bufferram[i].block == block &&
            this->bufferram[i].page == page &&
            this->bufferram[i].valid)
                return 1;

        return 0;
}

/**
 * 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 int onenand_update_bufferram(struct mtd_info *mtd, loff_t addr,
                int valid)
{
        struct onenand_chip *this = mtd->priv;
        int block, page;
        int i;

        block = (int) (addr >> this->erase_shift);
        page = (int) (addr >> this->page_shift);
        page &= this->page_mask;

        /* Invalidate BufferRAM */
        for (i = 0; i < MAX_BUFFERRAM; i++) {
                if (this->bufferram[i].block == block &&
                    this->bufferram[i].page == page)
                        this->bufferram[i].valid = 0;
        }

        /* Update BufferRAM */
        i = ONENAND_CURRENT_BUFFERRAM(this);
        this->bufferram[i].block = block;
        this->bufferram[i].page = page;
        this->bufferram[i].valid = valid;

        return 0;
}

/**
 * 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);
                        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;

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

/**
 * onenand_read - [MTD Interface] Read data from flash
 * @param mtd           MTD device structure
 * @param from          offset to read from
 * @param len           number of bytes to read
 * @param retlen        pointer to variable to store the number of read bytes
 * @param buf           the databuffer to put data
 *
 * Read with ecc
*/
static int onenand_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_ecc_stats stats;
        int read = 0, column;
        int thislen;
        int ret = 0;

        DEBUG(MTD_DEBUG_LEVEL3, "onenand_read: from = 0x%08x, len = %i\n", (unsigned int) from, (int) len);

        /* Do not allow reads past end of device */
        if ((from + len) > mtd->size) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_read: Attempt read beyond end of device\n");
                *retlen = 0;
                return -EINVAL;
        }

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

        /* TODO handling oob */

        stats = mtd->ecc_stats;
        while (read < len) {
                cond_resched();

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

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

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

                        ret = this->wait(mtd, FL_READING);
                        /* First copy data and check return value for ECC handling */
                        onenand_update_bufferram(mtd, from, !ret);
                }

                this->read_bufferram(mtd, ONENAND_DATARAM, buf, column, thislen);

                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_read: read failed = %d\n", ret);
                        goto out;
                }

                read += thislen;

                if (read == len)
                        break;

                from += thislen;
                buf += thislen;
        }

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

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

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

        return mtd->ecc_stats.corrected - stats.corrected ? -EUCLEAN : 0;
}

/**
 * onenand_do_read_oob - [MTD Interface] OneNAND read out-of-band
 * @param mtd           MTD device structure
 * @param from          offset to read from
 * @param len           number of bytes to read
 * @param retlen        pointer to variable to store the number of read bytes
 * @param buf           the databuffer to put data
 *
 * OneNAND read out-of-band data from the spare area
 */
int onenand_do_read_oob(struct mtd_info *mtd, loff_t from, size_t len,
                        size_t *retlen, u_char *buf)
{
        struct onenand_chip *this = mtd->priv;
        int read = 0, thislen, column;
        int ret = 0;

        DEBUG(MTD_DEBUG_LEVEL3, "onenand_read_oob: from = 0x%08x, len = %i\n", (unsigned int) from, (int) len);

        /* Initialize return length value */
        *retlen = 0;

        /* Do not allow reads past end of device */
        if (unlikely((from + len) > mtd->size)) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_read_oob: Attempt read beyond end of device\n");
                return -EINVAL;
        }

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

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

        while (read < len) {
                cond_resched();

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

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

                onenand_update_bufferram(mtd, from, 0);

                ret = this->wait(mtd, FL_READING);
                /* First copy data and check return value for ECC handling */

                this->read_bufferram(mtd, ONENAND_SPARERAM, buf, column, thislen);

                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_read_oob: read failed = 0x%x\n", ret);
                        goto out;
                }

                read += thislen;

                if (read == len)
                        break;

                buf += thislen;

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

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

        *retlen = read;
        return ret;
}

/**
 * onenand_read_oob - [MTD Interface] NAND write data and/or out-of-band
 * @mtd:        MTD device structure
 * @from:       offset to read from
 * @ops:        oob operation description structure
 */
static int onenand_read_oob(struct mtd_info *mtd, loff_t from,
                            struct mtd_oob_ops *ops)
{
        BUG_ON(ops->mode != MTD_OOB_PLACE);

        return onenand_do_read_oob(mtd, from + ops->ooboffs, ops->ooblen,
                                   &ops->oobretlen, ops->oobbuf);
}

#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
 * @param len           number of bytes to read and compare
 *
 */
static int onenand_verify_oob(struct mtd_info *mtd, const u_char *buf, loff_t to, int len)
{
        struct onenand_chip *this = mtd->priv;
        char *readp = this->page_buf;
        int column = to & (mtd->oobsize - 1);
        int status, i;

        this->command(mtd, ONENAND_CMD_READOOB, 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, readp, column, len);

        for(i = 0; i < len; i++)
                if (buf[i] != 0xFF && buf[i] != readp[i])
                        return -EBADMSG;

        return 0;
}

/**
 * onenand_verify_page - [GENERIC] verify the chip contents after a write
 * @param mtd           MTD device structure
 * @param buf           the databuffer to verify
 *
 * Check DataRAM area directly
 */
static int onenand_verify_page(struct mtd_info *mtd, u_char *buf, loff_t addr)
{
        struct onenand_chip *this = mtd->priv;
        void __iomem *dataram0, *dataram1;
        int ret = 0;

        /* In partial page write, just skip it */
        if ((addr & (mtd->writesize - 1)) != 0)
                return 0;

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

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

        onenand_update_bufferram(mtd, addr, 1);

        /* Check, if the two dataram areas are same */
        dataram0 = this->base + ONENAND_DATARAM;
        dataram1 = dataram0 + mtd->writesize;

        if (memcmp(dataram0, dataram1, mtd->writesize))
                return -EBADMSG;

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

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

/**
 * onenand_write - [MTD Interface] write buffer to FLASH
 * @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_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 written = 0;
        int ret = 0;
        int column, subpage;

        DEBUG(MTD_DEBUG_LEVEL3, "onenand_write: to = 0x%08x, len = %i\n", (unsigned int) to, (int) len);

        /* Initialize retlen, in case of early exit */
        *retlen = 0;

        /* Do not allow writes past end of device */
        if (unlikely((to + len) > mtd->size)) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_write: Attempt write to past end of device\n");
                return -EINVAL;
        }

        /* Reject writes, which are not page aligned */
        if (unlikely(NOTALIGNED(to)) || unlikely(NOTALIGNED(len))) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_write: Attempt to write not page aligned data\n");
                return -EINVAL;
        }

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

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

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

                cond_resched();

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

                /* Partial page write */
                if (subpage) {
                        bytes = min_t(int, bytes - column, (int) len);
                        memset(this->page_buf, 0xff, mtd->writesize);
                        memcpy(this->page_buf + column, buf, bytes);
                        wbuf = this->page_buf;
                        /* Even though partial write, we need page size */
                        thislen = mtd->writesize;
                }

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

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

                /* In partial page write we don't update bufferram */
                onenand_update_bufferram(mtd, to, !subpage);

                ret = this->wait(mtd, FL_WRITING);
                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_write: write filaed %d\n", ret);
                        break;
                }

                /* Only check verify write turn on */
                ret = onenand_verify_page(mtd, (u_char *) wbuf, to);
                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_write: verify failed %d\n", ret);
                        break;
                }

                written += thislen;

                if (written == len)
                        break;

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

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

        *retlen = written;

        return ret;
}

/**
 * onenand_do_write_oob - [Internal] 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
 *
 * OneNAND write out-of-band
 */
static int onenand_do_write_oob(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, ret = 0;
        int written = 0;

        DEBUG(MTD_DEBUG_LEVEL3, "onenand_write_oob: to = 0x%08x, len = %i\n", (unsigned int) to, (int) len);

        /* Initialize retlen, in case of early exit */
        *retlen = 0;

        /* Do not allow writes past end of device */
        if (unlikely((to + len) > mtd->size)) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_write_oob: Attempt write to past end of device\n");
                return -EINVAL;
        }

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

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

                cond_resched();

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

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

                /* We send data to spare ram with oobsize
                 * to prevent byte access */
                memset(this->page_buf, 0xff, mtd->oobsize);
                memcpy(this->page_buf + column, buf, thislen);
                this->write_bufferram(mtd, ONENAND_SPARERAM, this->page_buf, 0, mtd->oobsize);

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

                onenand_update_bufferram(mtd, to, 0);

                ret = this->wait(mtd, FL_WRITING);
                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_write_oob: write filaed %d\n", ret);
                        goto out;
                }

                ret = onenand_verify_oob(mtd, buf, to, thislen);
                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_write_oob: verify failed %d\n", ret);
                        goto out;
                }

                written += thislen;

                if (written == len)
                        break;

                to += thislen;
                buf += thislen;
        }

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

        *retlen = written;

        return ret;
}

/**
 * onenand_write_oob - [MTD Interface] NAND write data and/or out-of-band
 * @mtd:        MTD device structure
 * @from:       offset to read from
 * @ops:        oob operation description structure
 */
static int onenand_write_oob(struct mtd_info *mtd, loff_t to,
                             struct mtd_oob_ops *ops)
{
        BUG_ON(ops->mode != MTD_OOB_PLACE);

        return onenand_do_write_oob(mtd, to + ops->ooboffs, ops->ooblen,
                                    &ops->oobretlen, ops->oobbuf);
}

/**
 * onenand_block_checkbad - [GENERIC] Check if a block is marked bad
 * @param mtd           MTD device structure
 * @param ofs           offset from device start
 * @param getchip       0, if the chip is already selected
 * @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_checkbad(struct mtd_info *mtd, loff_t ofs, int getchip, 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);
}

/**
 * onenand_erase - [MTD Interface] erase block(s)
 * @param mtd           MTD device structure
 * @param instr         erase instruction
 *
 * Erase one ore 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;
        int len;
        int ret = 0;

        DEBUG(MTD_DEBUG_LEVEL3, "onenand_erase: start = 0x%08x, len = %i\n", (unsigned int) instr->addr, (unsigned int) instr->len);

        block_size = (1 << this->erase_shift);

        /* Start address must align on block boundary */
        if (unlikely(instr->addr & (block_size - 1))) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_erase: Unaligned address\n");
                return -EINVAL;
        }

        /* Length must align on block boundary */
        if (unlikely(instr->len & (block_size - 1))) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_erase: Length not block aligned\n");
                return -EINVAL;
        }

        /* Do not allow erase past end of device */
        if (unlikely((instr->len + instr->addr) > mtd->size)) {
                DEBUG(MTD_DEBUG_LEVEL0, "onenand_erase: Erase past end of device\n");
                return -EINVAL;
        }

        instr->fail_addr = 0xffffffff;

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

        /* Loop throught the pages */
        len = instr->len;
        addr = instr->addr;

        instr->state = MTD_ERASING;

        while (len) {
                cond_resched();

                /* Check if we have a bad block, we do not erase bad blocks */
                if (onenand_block_checkbad(mtd, addr, 0, 0)) {
                        printk (KERN_WARNING "onenand_erase: attempt to erase a bad block at addr 0x%08x\n", (unsigned int) addr);
                        instr->state = MTD_ERASE_FAILED;
                        goto erase_exit;
                }

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

                ret = this->wait(mtd, FL_ERASING);
                /* Check, if it is write protected */
                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0, "onenand_erase: Failed erase, block %d\n", (unsigned) (addr >> this->erase_shift));
                        instr->state = MTD_ERASE_FAILED;
                        instr->fail_addr = addr;
                        goto erase_exit;
                }

                len -= block_size;
                addr += block_size;
        }

        instr->state = MTD_ERASE_DONE;

erase_exit:

        ret = instr->state == MTD_ERASE_DONE ? 0 : -EIO;
        /* Do call back function */
        if (!ret)
                mtd_erase_callback(instr);

        /* 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)
{
        DEBUG(MTD_DEBUG_LEVEL3, "onenand_sync: called\n");

        /* 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)
{
        /* Check for invalid offset */
        if (ofs > mtd->size)
                return -EINVAL;

        return onenand_block_checkbad(mtd, ofs, 1, 0);
}

/**
 * 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};
        size_t retlen;
        int block;

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

        /* We write two bytes, so we dont have to mess with 16 bit access */
        ofs += mtd->oobsize + (bbm->badblockpos & ~0x01);
        return onenand_do_write_oob(mtd, ofs , 2, &retlen, buf);
}

/**
 * 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;
        }

        return this->block_markbad(mtd, ofs);
}

/**
 * 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
 *
 * 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 = ofs >> this->erase_shift;
        end = len >> this->erase_shift;

        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(start + end - 1, 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 "wp status = 0x%x\n", status);

                return 0;
        }

        /* Block lock scheme */
        for (block = start; block < start + 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);
                /* 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 "block = %d, wp status = 0x%x\n", 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, size_t len)
{
        return onenand_do_lock_cmd(mtd, ofs, len, ONENAND_CMD_LOCK);
}

/**
 * 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, size_t len)
{
        return onenand_do_lock_cmd(mtd, ofs, len, ONENAND_CMD_UNLOCK);
}

/**
 * onenand_check_lock_status - [OneNAND Interface] Check lock status
 * @param this          onenand chip data structure
 *
 * Check lock status
 */
static void 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 "block = %d, wp status = 0x%x\n", block, status);
        }
}

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

        if (this->options & ONENAND_HAS_UNLOCK_ALL) {
                /* 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;

                /* Workaround for all block unlock in DDP */
                if (this->device_id & ONENAND_DEVICE_IS_DDP) {
                        loff_t ofs;
                        size_t len;

                        /* 1st block on another chip */
                        ofs = this->chipsize >> 1;
                        len = 1 << this->erase_shift;

                        onenand_unlock(mtd, ofs, len);
                }

                onenand_check_lock_status(this);

                return 0;
        }

        onenand_unlock(mtd, 0x0, this->chipsize);

        return 0;
}

#ifdef CONFIG_MTD_ONENAND_OTP

/* Interal 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;
        int ret;

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

        ret = mtd->read(mtd, from, len, retlen, buf);

        /* 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 from          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 from, size_t len,
                size_t *retlen, u_char *buf)
{
        struct onenand_chip *this = mtd->priv;
        unsigned char *pbuf = buf;
        int ret;

        /* 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);

        ret = mtd->write(mtd, from, len, retlen, pbuf);

        /* 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;
        int ret;

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

        ret = onenand_do_write_oob(mtd, from, len, retlen, buf);

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

        return ret;
}

/**
 * onenand_otp_walk - [DEFAULT] Handle OTP operation
 * @param mtd           MTD device structure
 * @param from          The offset to read/write
 * @param len           number of bytes to read/write
 * @param retlen        pointer to variable to store the number of read bytes
 * @param buf           the databuffer to put/get data
 * @param action        do given action
 * @param mode          specify user and factory
 *
 * Handle OTP operation.
 */
static int onenand_otp_walk(struct mtd_info *mtd, loff_t from, size_t len,
                        size_t *retlen, u_char *buf,
                        otp_op_t action, int mode)
{
        struct onenand_chip *this = mtd->priv;
        int otp_pages;
        int density;
        int ret = 0;

        *retlen = 0;

        density = this->device_id >> ONENAND_DEVICE_DENSITY_SHIFT;
        if (density < ONENAND_DEVICE_DENSITY_512Mb)
                otp_pages = 20;
        else
                otp_pages = 10;

        if (mode == MTD_OTP_FACTORY) {
                from += mtd->writesize * otp_pages;
                otp_pages = 64 - otp_pages;
        }

        /* Check User/Factory boundary */
        if (((mtd->writesize * otp_pages) - (from + len)) < 0)
                return 0;

        while (len > 0 && otp_pages > 0) {
                if (!action) {  /* OTP Info functions */
                        struct otp_info *otpinfo;

                        len -= sizeof(struct otp_info);
                        if (len <= 0)
                                return -ENOSPC;

                        otpinfo = (struct otp_info *) buf;
                        otpinfo->start = from;
                        otpinfo->length = mtd->writesize;
                        otpinfo->locked = 0;

                        from += mtd->writesize;
                        buf += sizeof(struct otp_info);
                        *retlen += sizeof(struct otp_info);
                } else {
                        size_t tmp_retlen;
                        int size = len;

                        ret = action(mtd, from, len, &tmp_retlen, buf);

                        buf += size;
                        len -= size;
                        *retlen += size;

                        if (ret < 0)
                                return ret;
                }
                otp_pages--;
        }

        return 0;
}

/**
 * onenand_get_fact_prot_info - [MTD Interface] Read factory OTP info
 * @param mtd           MTD device structure
 * @param buf           the databuffer to put/get data
 * @param len           number of bytes to read
 *
 * Read factory OTP info.
 */
static int onenand_get_fact_prot_info(struct mtd_info *mtd,
                        struct otp_info *buf, size_t len)
{
        size_t retlen;
        int ret;

        ret = onenand_otp_walk(mtd, 0, len, &retlen, (u_char *) buf, NULL, MTD_OTP_FACTORY);

        return ret ? : retlen;
}

/**
 * onenand_read_fact_prot_reg - [MTD Interface] Read factory OTP 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 read bytes
 * @param buf           the databuffer to put/get data
 *
 * Read factory OTP area.
 */
static int onenand_read_fact_prot_reg(struct mtd_info *mtd, loff_t from,
                        size_t len, size_t *retlen, u_char *buf)
{
        return onenand_otp_walk(mtd, from, len, retlen, buf, do_otp_read, MTD_OTP_FACTORY);
}

/**
 * onenand_get_user_prot_info - [MTD Interface] Read user OTP info
 * @param mtd           MTD device structure
 * @param buf           the databuffer to put/get data
 * @param len           number of bytes to read
 *
 * Read user OTP info.
 */
static int onenand_get_user_prot_info(struct mtd_info *mtd,
                        struct otp_info *buf, size_t len)
{
        size_t retlen;
        int ret;

        ret = onenand_otp_walk(mtd, 0, len, &retlen, (u_char *) buf, NULL, MTD_OTP_USER);

        return ret ? : retlen;
}

/**
 * onenand_read_user_prot_reg - [MTD Interface] Read user OTP 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 read bytes
 * @param buf           the databuffer to put/get data
 *
 * Read user OTP area.
 */
static int onenand_read_user_prot_reg(struct mtd_info *mtd, loff_t from,
                        size_t len, size_t *retlen, u_char *buf)
{
        return onenand_otp_walk(mtd, from, len, retlen, buf, do_otp_read, MTD_OTP_USER);
}

/**
 * onenand_write_user_prot_reg - [MTD Interface] Write user OTP area
 * @param mtd           MTD device structure
 * @param from          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 user OTP area.
 */
static int onenand_write_user_prot_reg(struct mtd_info *mtd, loff_t from,
                        size_t len, size_t *retlen, u_char *buf)
{
        return onenand_otp_walk(mtd, from, len, retlen, buf, do_otp_write, MTD_OTP_USER);
}

/**
 * onenand_lock_user_prot_reg - [MTD Interface] Lock user OTP area
 * @param mtd           MTD device structure
 * @param from          The offset to lock
 * @param len           number of bytes to unlock
 *
 * Write lock mark on spare area in page 0 in OTP block
 */
static int onenand_lock_user_prot_reg(struct mtd_info *mtd, loff_t from,
                        size_t len)
{
        unsigned char oob_buf[64];
        size_t retlen;
        int ret;

        memset(oob_buf, 0xff, mtd->oobsize);
        /*
         * Note: OTP lock operation
         *       OTP block : 0xXXFC
         *       1st block : 0xXXF3 (If chip support)
         *       Both      : 0xXXF0 (If chip support)
         */
        oob_buf[ONENAND_OTP_LOCK_OFFSET] = 0xFC;

        /*
         * Write lock mark to 8th word of sector0 of page0 of the spare0.
         * We write 16 bytes spare area instead of 2 bytes.
         */
        from = 0;
        len = 16;

        ret = onenand_otp_walk(mtd, from, len, &retlen, oob_buf, do_otp_lock, MTD_OTP_USER);

        return ret ? : retlen;
}
#endif  /* CONFIG_MTD_ONENAND_OTP */

/**
 * onenand_lock_scheme - Check and set OneNAND lock scheme
 * @param mtd           MTD data structure
 *
 * Check and set OneNAND lock scheme
 */
static void onenand_lock_scheme(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;
        unsigned int density, process;

        /* Lock scheme depends on density and process */
        density = this->device_id >> ONENAND_DEVICE_DENSITY_SHIFT;
        process = this->version_id >> ONENAND_VERSION_PROCESS_SHIFT;

        /* Lock scheme */
        if (density >= ONENAND_DEVICE_DENSITY_1Gb) {
                /* A-Die has all block unlock */
                if (process) {
                        printk(KERN_DEBUG "Chip support all block unlock\n");
                        this->options |= ONENAND_HAS_UNLOCK_ALL;
                }
        } else {
                /* Some OneNAND has continues lock scheme */
                if (!process) {
                        printk(KERN_DEBUG "Lock scheme is Continues Lock\n");
                        this->options |= ONENAND_HAS_CONT_LOCK;
                }
        }
}

/**
 * onenand_print_device_info - Print device ID
 * @param device        device ID
 *
 * Print device ID
 */
static void onenand_print_device_info(int device, int version)
{
        int vcc, demuxed, ddp, density;

        vcc = device & ONENAND_DEVICE_VCC_MASK;
        demuxed = device & ONENAND_DEVICE_IS_DEMUX;
        ddp = device & ONENAND_DEVICE_IS_DDP;
        density = device >> ONENAND_DEVICE_DENSITY_SHIFT;
        printk(KERN_INFO "%sOneNAND%s %dMB %sV 16-bit (0x%02x)\n",
                demuxed ? "" : "Muxed ",
                ddp ? "(DDP)" : "",
                (16 << density),
                vcc ? "2.65/3.3" : "1.8",
                device);
        printk(KERN_DEBUG "OneNAND version = 0x%04x\n", version);
}

static const struct onenand_manufacturers onenand_manuf_ids[] = {
        {ONENAND_MFR_SAMSUNG, "Samsung"},
};

/**
 * onenand_check_maf - Check manufacturer ID
 * @param manuf         manufacturer ID
 *
 * Check manufacturer ID
 */
static int onenand_check_maf(int manuf)
{
        int size = ARRAY_SIZE(onenand_manuf_ids);
        char *name;
        int i;

        for (i = 0; i < size; i++)
                if (manuf == onenand_manuf_ids[i].id)
                        break;

        if (i < size)
                name = onenand_manuf_ids[i].name;
        else
                name = "Unknown";

        printk(KERN_DEBUG "OneNAND Manufacturer: %s (0x%0x)\n", name, manuf);

        return (i == size);
}

/**
 * onenand_probe - [OneNAND Interface] Probe the OneNAND device
 * @param mtd           MTD device structure
 *
 * OneNAND detection method:
 *   Compare the the values from command with ones from register
 */
static int onenand_probe(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;
        int bram_maf_id, bram_dev_id, maf_id, dev_id, ver_id;
        int density;
        int syscfg;

        /* Save system configuration 1 */
        syscfg = this->read_word(this->base + ONENAND_REG_SYS_CFG1);
        /* Clear Sync. Burst Read mode to read BootRAM */
        this->write_word((syscfg & ~ONENAND_SYS_CFG1_SYNC_READ), this->base + ONENAND_REG_SYS_CFG1);

        /* Send the command for reading device ID from BootRAM */
        this->write_word(ONENAND_CMD_READID, this->base + ONENAND_BOOTRAM);

        /* Read manufacturer and device IDs from BootRAM */
        bram_maf_id = this->read_word(this->base + ONENAND_BOOTRAM + 0x0);
        bram_dev_id = this->read_word(this->base + ONENAND_BOOTRAM + 0x2);

        /* Reset OneNAND to read default register values */
        this->write_word(ONENAND_CMD_RESET, this->base + ONENAND_BOOTRAM);
        /* Wait reset */
        this->wait(mtd, FL_RESETING);

        /* Restore system configuration 1 */
        this->write_word(syscfg, this->base + ONENAND_REG_SYS_CFG1);

        /* Check manufacturer ID */
        if (onenand_check_maf(bram_maf_id))
                return -ENXIO;

        /* Read manufacturer and device IDs from Register */
        maf_id = this->read_word(this->base + ONENAND_REG_MANUFACTURER_ID);
        dev_id = this->read_word(this->base + ONENAND_REG_DEVICE_ID);
        ver_id = this->read_word(this->base + ONENAND_REG_VERSION_ID);

        /* Check OneNAND device */
        if (maf_id != bram_maf_id || dev_id != bram_dev_id)
                return -ENXIO;

        /* Flash device information */
        onenand_print_device_info(dev_id, ver_id);
        this->device_id = dev_id;
        this->version_id = ver_id;

        density = dev_id >> ONENAND_DEVICE_DENSITY_SHIFT;
        this->chipsize = (16 << density) << 20;
        /* Set density mask. it is used for DDP */
        this->density_mask = (1 << (density + 6));

        /* OneNAND page size & block size */
        /* The data buffer size is equal to page size */
        mtd->writesize = this->read_word(this->base + ONENAND_REG_DATA_BUFFER_SIZE);
        mtd->oobsize = mtd->writesize >> 5;
        /* Pagers per block is always 64 in OneNAND */
        mtd->erasesize = mtd->writesize << 6;

        this->erase_shift = ffs(mtd->erasesize) - 1;
        this->page_shift = ffs(mtd->writesize) - 1;
        this->ppb_shift = (this->erase_shift - this->page_shift);
        this->page_mask = (mtd->erasesize / mtd->writesize) - 1;

        /* REVIST: Multichip handling */

        mtd->size = this->chipsize;

        /* Check OneNAND lock scheme */
        onenand_lock_scheme(mtd);

        return 0;
}

/**
 * onenand_suspend - [MTD Interface] Suspend the OneNAND flash
 * @param mtd           MTD device structure
 */
static int onenand_suspend(struct mtd_info *mtd)
{
        return onenand_get_device(mtd, FL_PM_SUSPENDED);
}

/**
 * onenand_resume - [MTD Interface] Resume the OneNAND flash
 * @param mtd           MTD device structure
 */
static void onenand_resume(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;

        if (this->state == FL_PM_SUSPENDED)
                onenand_release_device(mtd);
        else
                printk(KERN_ERR "resume() called for the chip which is not"
                                "in suspended state\n");
}

/**
 * onenand_scan - [OneNAND Interface] Scan for the OneNAND device
 * @param mtd           MTD device structure
 * @param maxchips      Number of chips to scan for
 *
 * This fills out all the not initialized function pointers
 * with the defaults.
 * The flash ID is read and the mtd/chip structures are
 * filled with the appropriate values.
 */
int onenand_scan(struct mtd_info *mtd, int maxchips)
{
        struct onenand_chip *this = mtd->priv;

        if (!this->read_word)
                this->read_word = onenand_readw;
        if (!this->write_word)
                this->write_word = onenand_writew;

        if (!this->command)
                this->command = onenand_command;
        if (!this->wait)
                onenand_setup_wait(mtd);

        if (!this->read_bufferram)
                this->read_bufferram = onenand_read_bufferram;
        if (!this->write_bufferram)
                this->write_bufferram = onenand_write_bufferram;

        if (!this->block_markbad)
                this->block_markbad = onenand_default_block_markbad;
        if (!this->scan_bbt)
                this->scan_bbt = onenand_default_bbt;

        if (onenand_probe(mtd))
                return -ENXIO;

        /* Set Sync. Burst Read after probing */
        if (this->mmcontrol) {
                printk(KERN_INFO "OneNAND Sync. Burst Read support\n");
                this->read_bufferram = onenand_sync_read_bufferram;
        }

        /* Allocate buffers, if necessary */
        if (!this->page_buf) {
                size_t len;
                len = mtd->writesize + mtd->oobsize;
                this->page_buf = kmalloc(len, GFP_KERNEL);
                if (!this->page_buf) {
                        printk(KERN_ERR "onenand_scan(): Can't allocate page_buf\n");
                        return -ENOMEM;
                }
                this->options |= ONENAND_PAGEBUF_ALLOC;
        }

        this->state = FL_READY;
        init_waitqueue_head(&this->wq);
        spin_lock_init(&this->chip_lock);

        /*
         * Allow subpage writes up to oobsize.
         */
        switch (mtd->oobsize) {
        case 64:
                this->ecclayout = &onenand_oob_64;
                mtd->subpage_sft = 2;
                break;

        case 32:
                this->ecclayout = &onenand_oob_32;
                mtd->subpage_sft = 1;
                break;

        default:
                printk(KERN_WARNING "No OOB scheme defined for oobsize %d\n",
                        mtd->oobsize);
                mtd->subpage_sft = 0;
                /* To prevent kernel oops */
                this->ecclayout = &onenand_oob_32;
                break;
        }

        this->subpagesize = mtd->writesize >> mtd->subpage_sft;
        mtd->ecclayout = this->ecclayout;

        /* Fill in remaining MTD driver data */
        mtd->type = MTD_NANDFLASH;
        mtd->flags = MTD_CAP_NANDFLASH;
        mtd->ecctype = MTD_ECC_SW;
        mtd->erase = onenand_erase;
        mtd->point = NULL;
        mtd->unpoint = NULL;
        mtd->read = onenand_read;
        mtd->write = onenand_write;
        mtd->read_oob = onenand_read_oob;
        mtd->write_oob = onenand_write_oob;
#ifdef CONFIG_MTD_ONENAND_OTP
        mtd->get_fact_prot_info = onenand_get_fact_prot_info;
        mtd->read_fact_prot_reg = onenand_read_fact_prot_reg;
        mtd->get_user_prot_info = onenand_get_user_prot_info;
        mtd->read_user_prot_reg = onenand_read_user_prot_reg;
        mtd->write_user_prot_reg = onenand_write_user_prot_reg;
        mtd->lock_user_prot_reg = onenand_lock_user_prot_reg;
#endif
        mtd->sync = onenand_sync;
        mtd->lock = onenand_lock;
        mtd->unlock = onenand_unlock;
        mtd->suspend = onenand_suspend;
        mtd->resume = onenand_resume;
        mtd->block_isbad = onenand_block_isbad;
        mtd->block_markbad = onenand_block_markbad;
        mtd->owner = THIS_MODULE;

        /* Unlock whole block */
        onenand_unlock_all(mtd);

        return this->scan_bbt(mtd);
}

/**
 * onenand_release - [OneNAND Interface] Free resources held by the OneNAND device
 * @param mtd           MTD device structure
 */
void onenand_release(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;

#ifdef CONFIG_MTD_PARTITIONS
        /* Deregister partitions */
        del_mtd_partitions (mtd);
#endif
        /* Deregister the device */
        del_mtd_device (mtd);

        /* Free bad block table memory, if allocated */
        if (this->bbm)
                kfree(this->bbm);
        /* Buffer allocated by onenand_scan */
        if (this->options & ONENAND_PAGEBUF_ALLOC)
                kfree(this->page_buf);
}

EXPORT_SYMBOL_GPL(onenand_scan);
EXPORT_SYMBOL_GPL(onenand_release);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kyungmin Park <kyungmin.park@samsung.com>");
MODULE_DESCRIPTION("Generic OneNAND flash driver code");