nand-createbbt.patch

[u-boot-openmoko/mini2440.git] / drivers / mtd / onenand / onenand_base.c

/*
 *  linux/drivers/mtd/onenand/onenand_base.c
 *
 *  Copyright (C) 2005-2007 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 <common.h>

#ifdef CONFIG_CMD_ONENAND

#include <linux/mtd/compat.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/onenand.h>

#include <asm/io.h>
#include <asm/errno.h>

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 device        the device id
 * @param block         the block
 * @return              translated block address if DDP, otherwise same
 *
 * Setup Start Address 1 Register (F100h)
 */
static int onenand_block_address(int device, int block)
{
        if (device & ONENAND_DEVICE_IS_DDP) {
                /* Device Flash Core select, NAND Flash Block Address */
                int dfs = 0, density, mask;

                density = device >> ONENAND_DEVICE_DENSITY_SHIFT;
                mask = (1 << (density + 6));

                if (block & mask)
                        dfs = 1;

                return (dfs << ONENAND_DDP_SHIFT) | (block & (mask - 1));
        }

        return block;
}

/**
 * onenand_bufferram_address - [DEFAULT] Get bufferram address
 * @param device        the device id
 * @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(int device, int block)
{
        if (device & ONENAND_DEVICE_IS_DDP) {
                /* Device BufferRAM Select */
                int dbs = 0, density, mask;

                density = device >> ONENAND_DEVICE_DENSITY_SHIFT;
                mask = (1 << (density + 6));

                if (block & 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;
        int block, page;
        /* Now we use page size operation */
        int sectors = 4, count = 4;

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

        case ONENAND_CMD_ERASE:
        case ONENAND_CMD_BUFFERRAM:
                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->device_id, 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->device_id, block);
                this->write_word(value,
                                 this->base + ONENAND_REG_START_ADDRESS1);
        }

        if (page != -1) {
                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->device_id, 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 int flags = ONENAND_INT_MASTER;
        unsigned int interrupt = 0;
        unsigned int ctrl, ecc;

        while (1) {
                interrupt = this->read_word(this->base + ONENAND_REG_INTERRUPT);
                if (interrupt & flags)
                        break;
        }

        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);
                return -EAGAIN;
        }

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

        if (interrupt & ONENAND_INT_READ) {
                ecc = this->read_word(this->base + ONENAND_REG_ECC_STATUS);
                if (ecc & ONENAND_ECC_2BIT_ALL) {
                        DEBUG(MTD_DEBUG_LEVEL0,
                              "onenand_wait: ECC error = 0x%04x\n", ecc);
                        return -EBADMSG;
                }
        }

        return 0;
}

/**
 * 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->oobblock;
                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);

        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);

        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);

        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 void onenand_get_device(struct mtd_info *mtd, int new_state)
{
        /* Do nothing */
}

/**
 * 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)
{
        /* Do nothing */
}

/**
 * onenand_read_ecc - [MTD Interface] Read data with ECC
 * @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
 * @param oob_buf       filesystem supplied oob data buffer
 * @param oobsel        oob selection structure
 *
 * OneNAND read with ECC
 */
static int onenand_read_ecc(struct mtd_info *mtd, loff_t from, size_t len,
                            size_t * retlen, u_char * buf,
                            u_char * oob_buf, struct nand_oobinfo *oobsel)
{
        struct onenand_chip *this = mtd->priv;
        int read = 0, column;
        int thislen;
        int ret = 0;

        DEBUG(MTD_DEBUG_LEVEL3, "onenand_read_ecc: 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_ecc: 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);

        while (read < len) {
                thislen = min_t(int, mtd->oobblock, len - read);

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

                if (!onenand_check_bufferram(mtd, from)) {
                        this->command(mtd, ONENAND_CMD_READ, from,
                                      mtd->oobblock);
                        ret = this->wait(mtd, FL_READING);
                        /* First copy data and check return value for ECC handling */
                        onenand_update_bufferram(mtd, from, 1);
                }

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

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

                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0,
                              "onenand_read_ecc: read failed = %d\n", ret);
                        break;
                }

                from += thislen;
                buf += thislen;
        }

        /* 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;
        return ret;
}

/**
 * onenand_read - [MTD Interface] MTD compability function for onenand_read_ecc
 * @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
 *
 * This function simply calls onenand_read_ecc with oob buffer and oobsel = NULL
*/
int onenand_read(struct mtd_info *mtd, loff_t from, size_t len,
                 size_t * retlen, u_char * buf)
{
        return onenand_read_ecc(mtd, from, len, retlen, buf, NULL, NULL);
}

/**
 * onenand_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_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) {
                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);

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

                if (ret) {
                        DEBUG(MTD_DEBUG_LEVEL0,
                              "onenand_read_oob: read failed = %d\n", ret);
                        break;
                }

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

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

        *retlen = read;
        return ret;
}

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

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

        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->oobblock;

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

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

#define NOTALIGNED(x)   ((x & (mtd->oobblock - 1)) != 0)

/**
 * onenand_write_ecc - [MTD Interface] OneNAND write with ECC
 * @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 eccbuf        filesystem supplied oob data buffer
 * @param oobsel        oob selection structure
 *
 * OneNAND write with ECC
 */
static int onenand_write_ecc(struct mtd_info *mtd, loff_t to, size_t len,
                             size_t * retlen, const u_char * buf,
                             u_char * eccbuf, struct nand_oobinfo *oobsel)
{
        struct onenand_chip *this = mtd->priv;
        int written = 0;
        int ret = 0;

        DEBUG(MTD_DEBUG_LEVEL3, "onenand_write_ecc: 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_ecc: 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_ecc: Attempt to write not page aligned data\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->oobblock, len - written);

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

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

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

                onenand_update_bufferram(mtd, to, 1);

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

                written += thislen;

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

                if (written == len)
                        break;

                to += thislen;
                buf += thislen;
        }

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

        *retlen = written;

        return ret;
}

/**
 * onenand_write - [MTD Interface] compability function for onenand_write_ecc
 * @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
 *
 * This function simply calls onenand_write_ecc
 * with oob buffer and oobsel = NULL
 */
int onenand_write(struct mtd_info *mtd, loff_t to, size_t len,
                  size_t * retlen, const u_char * buf)
{
        return onenand_write_ecc(mtd, to, len, retlen, buf, NULL, NULL);
}

/**
 * onenand_write_oob - [MTD Interface] 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
 */
int onenand_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, status;
        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);

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

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

                this->write_bufferram(mtd, ONENAND_SPARERAM, ffchars, 0,
                                      mtd->oobsize);
                this->write_bufferram(mtd, ONENAND_SPARERAM, buf, column,
                                      thislen);

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

                onenand_update_bufferram(mtd, to, 0);

                status = this->wait(mtd, FL_WRITING);
                if (status)
                        break;

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

                to += thislen;
                buf += thislen;
        }

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

        *retlen = written;

        return 0;
}

/**
 * onenand_erase - [MTD Interface] erase block(s)
 * @param mtd           MTD device structure
 * @param instr         erase instruction
 *
 * Erase one ore more blocks
 */
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) {

                /* TODO Check badblock */

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

                ret = this->wait(mtd, FL_ERASING);
                /* Check, if it is write protected */
                if (ret) {
                        if (ret == -EPERM)
                                DEBUG(MTD_DEBUG_LEVEL0,
                                      "onenand_erase: Device is write protected!!!\n");
                        else
                                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
 */
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
 */
int onenand_block_isbad(struct mtd_info *mtd, loff_t ofs)
{
        /*
         * TODO
         * 1. Bad block table (BBT)
         *   -> using NAND BBT to support JFFS2
         * 2. Bad block management (BBM)
         *   -> bad block replace scheme
         *
         * Currently we do nothing
         */
        return 0;
}

/**
 * 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
 */
int onenand_block_markbad(struct mtd_info *mtd, loff_t ofs)
{
        /* see above */
        return 0;
}

/**
 * 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
 */
int onenand_unlock(struct mtd_info *mtd, loff_t ofs, size_t len)
{
        struct onenand_chip *this = mtd->priv;
        int start, end, block, value, status;

        start = ofs >> this->erase_shift;
        end = len >> this->erase_shift;

        /* Continuous lock scheme */
        if (this->options & ONENAND_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 - 1,
                                 this->base + ONENAND_REG_END_BLOCK_ADDRESS);
                /* Write unlock command */
                this->command(mtd, ONENAND_CMD_UNLOCK, 0, 0);

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

                /* 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 & ONENAND_WP_US))
                        printk(KERN_ERR "wp status = 0x%x\n", status);

                return 0;
        }

        /* Block lock scheme */
        for (block = start; block < end; block++) {
                /* Set start block address */
                this->write_word(block,
                                 this->base + ONENAND_REG_START_BLOCK_ADDRESS);
                /* Write unlock command */
                this->command(mtd, ONENAND_CMD_UNLOCK, 0, 0);

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

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

                /* Set block address for read block status */
                value = onenand_block_address(this->device_id, block);
                this->write_word(value,
                                 this->base + ONENAND_REG_START_ADDRESS1);

                /* 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);
        }

        return 0;
}

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

        if (!verbose)
                return;

        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);
}

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

/**
 * onenand_check_maf - Check manufacturer ID
 * @param manuf         manufacturer ID
 *
 * Check manufacturer ID
 */
static int onenand_check_maf(int manuf)
{
        int i;

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

#ifdef ONENAND_DEBUG
        printk(KERN_DEBUG "OneNAND Manufacturer: %s (0x%0x)\n",
               onenand_manuf_ids[i].name, manuf);
#endif

        return (i != ONENAND_MFR_UNKNOWN);
}

/**
 * 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;
        int version_id;
        int density;

        /* 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);

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

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

        {
                int i;
                for (i = 0; i < 10000; i++) ;
        }

        /* 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);

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

        /* FIXME : Current OneNAND MTD doesn't support Flex-OneNAND */
        if (dev_id & (1 << 9)) {
                printk("Not yet support Flex-OneNAND\n");
                return -ENXIO;
        }

        /* Flash device information */
        onenand_print_device_info(dev_id, 0);
        this->device_id = dev_id;

        density = dev_id >> ONENAND_DEVICE_DENSITY_SHIFT;
        this->chipsize = (16 << density) << 20;

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

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

        /* REVIST: Multichip handling */

        mtd->size = this->chipsize;

        /* Version ID */
        version_id = this->read_word(this->base + ONENAND_REG_VERSION_ID);
#ifdef ONENAND_DEBUG
        printk(KERN_DEBUG "OneNAND version = 0x%04x\n", version_id);
#endif

        /* Lock scheme */
        if (density <= ONENAND_DEVICE_DENSITY_512Mb &&
            !(version_id >> ONENAND_VERSION_PROCESS_SHIFT)) {
                printk(KERN_INFO "Lock scheme is Continues Lock\n");
                this->options |= ONENAND_CONT_LOCK;
        }

        return 0;
}

/**
 * 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)
                this->wait = onenand_wait;

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

        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;
        }

        onenand_unlock(mtd, 0, mtd->size);

        return onenand_default_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)
{
}

#endif /* CONFIG_CMD_ONENAND */