/* Freescale Enhanced Local Bus Controller NAND driver
 *
 * Copyright © 2006-2007, 2010 Freescale Semiconductor
 *
 * Authors: Nick Spence <nick.spence@freescale.com>,
 *          Scott Wood <scottwood@freescale.com>
 *          Jack Lan <jack.lan@freescale.com>
 *          Roy Zang <tie-fei.zang@freescale.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/interrupt.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/nand_ecc.h>
#include <linux/mtd/partitions.h>

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

#define MAX_BANKS 8
#define ERR_BYTE 0xFF /* Value returned for read bytes when read failed */
#define FCM_TIMEOUT_MSECS 500 /* Maximum number of mSecs to wait for FCM */

/* mtd information per set */

struct fsl_elbc_mtd {
        struct nand_chip chip;
        struct fsl_lbc_ctrl *ctrl;

        struct device *dev;
        int bank;               /* Chip select bank number           */
        u8 __iomem *vbase;      /* Chip select base virtual address  */
        int page_size;          /* NAND page size (0=512, 1=2048)    */
        unsigned int fmr;       /* FCM Flash Mode Register value     */
};

/* Freescale eLBC FCM controller information */

struct fsl_elbc_fcm_ctrl {
        struct nand_hw_control controller;
        struct fsl_elbc_mtd *chips[MAX_BANKS];

        u8 __iomem *addr;        /* Address of assigned FCM buffer        */
        unsigned int page;       /* Last page written to / read from      */
        unsigned int read_bytes; /* Number of bytes read during command   */
        unsigned int column;     /* Saved column from SEQIN               */
        unsigned int index;      /* Pointer to next byte to 'read'        */
        unsigned int status;     /* status read from LTESR after last op  */
        unsigned int mdr;        /* UPM/FCM Data Register value           */
        unsigned int use_mdr;    /* Non zero if the MDR is to be set      */
        unsigned int oob;        /* Non zero if operating on OOB data     */
        unsigned int counter;    /* counter for the initializations       */
        unsigned int max_bitflips;  /* Saved during READ0 cmd             */
};

/* These map to the positions used by the FCM hardware ECC generator */

static int fsl_elbc_ooblayout_ecc(struct mtd_info *mtd, int section,
                                  struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);

        if (section >= chip->ecc.steps)
                return -ERANGE;

        oobregion->offset = (16 * section) + 6;
        if (priv->fmr & FMR_ECCM)
                oobregion->offset += 2;

        oobregion->length = chip->ecc.bytes;

        return 0;
}

static int fsl_elbc_ooblayout_free(struct mtd_info *mtd, int section,
                                   struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);

        if (section > chip->ecc.steps)
                return -ERANGE;

        if (!section) {
                oobregion->offset = 0;
                if (mtd->writesize > 512)
                        oobregion->offset++;
                oobregion->length = (priv->fmr & FMR_ECCM) ? 7 : 5;
        } else {
                oobregion->offset = (16 * section) -
                                    ((priv->fmr & FMR_ECCM) ? 5 : 7);
                if (section < chip->ecc.steps)
                        oobregion->length = 13;
                else
                        oobregion->length = mtd->oobsize - oobregion->offset;
        }

        return 0;
}

static const struct mtd_ooblayout_ops fsl_elbc_ooblayout_ops = {
        .ecc = fsl_elbc_ooblayout_ecc,
        .free = fsl_elbc_ooblayout_free,
};

/*
 * ELBC may use HW ECC, so that OOB offsets, that NAND core uses for bbt,
 * interfere with ECC positions, that's why we implement our own descriptors.
 * OOB {11, 5}, works for both SP and LP chips, with ECCM = 1 and ECCM = 0.
 */
static u8 bbt_pattern[] = {'B', 'b', 't', '0' };
static u8 mirror_pattern[] = {'1', 't', 'b', 'B' };

static struct nand_bbt_descr bbt_main_descr = {
        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE |
                   NAND_BBT_2BIT | NAND_BBT_VERSION,
        .offs = 11,
        .len = 4,
        .veroffs = 15,
        .maxblocks = 4,
        .pattern = bbt_pattern,
};

static struct nand_bbt_descr bbt_mirror_descr = {
        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE |
                   NAND_BBT_2BIT | NAND_BBT_VERSION,
        .offs = 11,
        .len = 4,
        .veroffs = 15,
        .maxblocks = 4,
        .pattern = mirror_pattern,
};

/*=================================*/

/*
 * Set up the FCM hardware block and page address fields, and the fcm
 * structure addr field to point to the correct FCM buffer in memory
 */
static void set_addr(struct mtd_info *mtd, int column, int page_addr, int oob)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_lbc_ctrl *ctrl = priv->ctrl;
        struct fsl_lbc_regs __iomem *lbc = ctrl->regs;
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = ctrl->nand;
        int buf_num;

        elbc_fcm_ctrl->page = page_addr;

        if (priv->page_size) {
                /*
                 * large page size chip : FPAR[PI] save the lowest 6 bits,
                 *                        FBAR[BLK] save the other bits.
                 */
                out_be32(&lbc->fbar, page_addr >> 6);
                out_be32(&lbc->fpar,
                         ((page_addr << FPAR_LP_PI_SHIFT) & FPAR_LP_PI) |
                         (oob ? FPAR_LP_MS : 0) | column);
                buf_num = (page_addr & 1) << 2;
        } else {
                /*
                 * small page size chip : FPAR[PI] save the lowest 5 bits,
                 *                        FBAR[BLK] save the other bits.
                 */
                out_be32(&lbc->fbar, page_addr >> 5);
                out_be32(&lbc->fpar,
                         ((page_addr << FPAR_SP_PI_SHIFT) & FPAR_SP_PI) |
                         (oob ? FPAR_SP_MS : 0) | column);
                buf_num = page_addr & 7;
        }

        elbc_fcm_ctrl->addr = priv->vbase + buf_num * 1024;
        elbc_fcm_ctrl->index = column;

        /* for OOB data point to the second half of the buffer */
        if (oob)
                elbc_fcm_ctrl->index += priv->page_size ? 2048 : 512;

        dev_vdbg(priv->dev, "set_addr: bank=%d, "
                            "elbc_fcm_ctrl->addr=0x%p (0x%p), "
                            "index %x, pes %d ps %d\n",
                 buf_num, elbc_fcm_ctrl->addr, priv->vbase,
                 elbc_fcm_ctrl->index,
                 chip->phys_erase_shift, chip->page_shift);
}

/*
 * execute FCM command and wait for it to complete
 */
static int fsl_elbc_run_command(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_lbc_ctrl *ctrl = priv->ctrl;
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = ctrl->nand;
        struct fsl_lbc_regs __iomem *lbc = ctrl->regs;

        /* Setup the FMR[OP] to execute without write protection */
        out_be32(&lbc->fmr, priv->fmr | 3);
        if (elbc_fcm_ctrl->use_mdr)
                out_be32(&lbc->mdr, elbc_fcm_ctrl->mdr);

        dev_vdbg(priv->dev,
                 "fsl_elbc_run_command: fmr=%08x fir=%08x fcr=%08x\n",
                 in_be32(&lbc->fmr), in_be32(&lbc->fir), in_be32(&lbc->fcr));
        dev_vdbg(priv->dev,
                 "fsl_elbc_run_command: fbar=%08x fpar=%08x "
                 "fbcr=%08x bank=%d\n",
                 in_be32(&lbc->fbar), in_be32(&lbc->fpar),
                 in_be32(&lbc->fbcr), priv->bank);

        ctrl->irq_status = 0;
        /* execute special operation */
        out_be32(&lbc->lsor, priv->bank);

        /* wait for FCM complete flag or timeout */
        wait_event_timeout(ctrl->irq_wait, ctrl->irq_status,
                           FCM_TIMEOUT_MSECS * HZ/1000);
        elbc_fcm_ctrl->status = ctrl->irq_status;
        /* store mdr value in case it was needed */
        if (elbc_fcm_ctrl->use_mdr)
                elbc_fcm_ctrl->mdr = in_be32(&lbc->mdr);

        elbc_fcm_ctrl->use_mdr = 0;

        if (elbc_fcm_ctrl->status != LTESR_CC) {
                dev_info(priv->dev,
                         "command failed: fir %x fcr %x status %x mdr %x\n",
                         in_be32(&lbc->fir), in_be32(&lbc->fcr),
                         elbc_fcm_ctrl->status, elbc_fcm_ctrl->mdr);
                return -EIO;
        }

        if (chip->ecc.mode != NAND_ECC_HW)
                return 0;

        elbc_fcm_ctrl->max_bitflips = 0;

        if (elbc_fcm_ctrl->read_bytes == mtd->writesize + mtd->oobsize) {
                uint32_t lteccr = in_be32(&lbc->lteccr);
                /*
                 * if command was a full page read and the ELBC
                 * has the LTECCR register, then bits 12-15 (ppc order) of
                 * LTECCR indicates which 512 byte sub-pages had fixed errors.
                 * bits 28-31 are uncorrectable errors, marked elsewhere.
                 * for small page nand only 1 bit is used.
                 * if the ELBC doesn't have the lteccr register it reads 0
                 * FIXME: 4 bits can be corrected on NANDs with 2k pages, so
                 * count the number of sub-pages with bitflips and update
                 * ecc_stats.corrected accordingly.
                 */
                if (lteccr & 0x000F000F)
                        out_be32(&lbc->lteccr, 0x000F000F); /* clear lteccr */
                if (lteccr & 0x000F0000) {
                        mtd->ecc_stats.corrected++;
                        elbc_fcm_ctrl->max_bitflips = 1;
                }
        }

        return 0;
}

static void fsl_elbc_do_read(struct nand_chip *chip, int oob)
{
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_lbc_ctrl *ctrl = priv->ctrl;
        struct fsl_lbc_regs __iomem *lbc = ctrl->regs;

        if (priv->page_size) {
                out_be32(&lbc->fir,
                         (FIR_OP_CM0 << FIR_OP0_SHIFT) |
                         (FIR_OP_CA  << FIR_OP1_SHIFT) |
                         (FIR_OP_PA  << FIR_OP2_SHIFT) |
                         (FIR_OP_CM1 << FIR_OP3_SHIFT) |
                         (FIR_OP_RBW << FIR_OP4_SHIFT));

                out_be32(&lbc->fcr, (NAND_CMD_READ0 << FCR_CMD0_SHIFT) |
                                    (NAND_CMD_READSTART << FCR_CMD1_SHIFT));
        } else {
                out_be32(&lbc->fir,
                         (FIR_OP_CM0 << FIR_OP0_SHIFT) |
                         (FIR_OP_CA  << FIR_OP1_SHIFT) |
                         (FIR_OP_PA  << FIR_OP2_SHIFT) |
                         (FIR_OP_RBW << FIR_OP3_SHIFT));

                if (oob)
                        out_be32(&lbc->fcr, NAND_CMD_READOOB << FCR_CMD0_SHIFT);
                else
                        out_be32(&lbc->fcr, NAND_CMD_READ0 << FCR_CMD0_SHIFT);
        }
}

/* cmdfunc send commands to the FCM */
static void fsl_elbc_cmdfunc(struct mtd_info *mtd, unsigned int command,
                             int column, int page_addr)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_lbc_ctrl *ctrl = priv->ctrl;
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = ctrl->nand;
        struct fsl_lbc_regs __iomem *lbc = ctrl->regs;

        elbc_fcm_ctrl->use_mdr = 0;

        /* clear the read buffer */
        elbc_fcm_ctrl->read_bytes = 0;
        if (command != NAND_CMD_PAGEPROG)
                elbc_fcm_ctrl->index = 0;

        switch (command) {
        /* READ0 and READ1 read the entire buffer to use hardware ECC. */
        case NAND_CMD_READ1:
                column += 256;

        /* fall-through */
        case NAND_CMD_READ0:
                dev_dbg(priv->dev,
                        "fsl_elbc_cmdfunc: NAND_CMD_READ0, page_addr:"
                        " 0x%x, column: 0x%x.\n", page_addr, column);


                out_be32(&lbc->fbcr, 0); /* read entire page to enable ECC */
                set_addr(mtd, 0, page_addr, 0);

                elbc_fcm_ctrl->read_bytes = mtd->writesize + mtd->oobsize;
                elbc_fcm_ctrl->index += column;

                fsl_elbc_do_read(chip, 0);
                fsl_elbc_run_command(mtd);
                return;

        /* READOOB reads only the OOB because no ECC is performed. */
        case NAND_CMD_READOOB:
                dev_vdbg(priv->dev,
                         "fsl_elbc_cmdfunc: NAND_CMD_READOOB, page_addr:"
                         " 0x%x, column: 0x%x.\n", page_addr, column);

                out_be32(&lbc->fbcr, mtd->oobsize - column);
                set_addr(mtd, column, page_addr, 1);

                elbc_fcm_ctrl->read_bytes = mtd->writesize + mtd->oobsize;

                fsl_elbc_do_read(chip, 1);
                fsl_elbc_run_command(mtd);
                return;

        case NAND_CMD_READID:
        case NAND_CMD_PARAM:
                dev_vdbg(priv->dev, "fsl_elbc_cmdfunc: NAND_CMD %x\n", command);

                out_be32(&lbc->fir, (FIR_OP_CM0 << FIR_OP0_SHIFT) |
                                    (FIR_OP_UA  << FIR_OP1_SHIFT) |
                                    (FIR_OP_RBW << FIR_OP2_SHIFT));
                out_be32(&lbc->fcr, command << FCR_CMD0_SHIFT);
                /*
                 * although currently it's 8 bytes for READID, we always read
                 * the maximum 256 bytes(for PARAM)
                 */
                out_be32(&lbc->fbcr, 256);
                elbc_fcm_ctrl->read_bytes = 256;
                elbc_fcm_ctrl->use_mdr = 1;
                elbc_fcm_ctrl->mdr = column;
                set_addr(mtd, 0, 0, 0);
                fsl_elbc_run_command(mtd);
                return;

        /* ERASE1 stores the block and page address */
        case NAND_CMD_ERASE1:
                dev_vdbg(priv->dev,
                         "fsl_elbc_cmdfunc: NAND_CMD_ERASE1, "
                         "page_addr: 0x%x.\n", page_addr);
                set_addr(mtd, 0, page_addr, 0);
                return;

        /* ERASE2 uses the block and page address from ERASE1 */
        case NAND_CMD_ERASE2:
                dev_vdbg(priv->dev, "fsl_elbc_cmdfunc: NAND_CMD_ERASE2.\n");

                out_be32(&lbc->fir,
                         (FIR_OP_CM0 << FIR_OP0_SHIFT) |
                         (FIR_OP_PA  << FIR_OP1_SHIFT) |
                         (FIR_OP_CM2 << FIR_OP2_SHIFT) |
                         (FIR_OP_CW1 << FIR_OP3_SHIFT) |
                         (FIR_OP_RS  << FIR_OP4_SHIFT));

                out_be32(&lbc->fcr,
                         (NAND_CMD_ERASE1 << FCR_CMD0_SHIFT) |
                         (NAND_CMD_STATUS << FCR_CMD1_SHIFT) |
                         (NAND_CMD_ERASE2 << FCR_CMD2_SHIFT));

                out_be32(&lbc->fbcr, 0);
                elbc_fcm_ctrl->read_bytes = 0;
                elbc_fcm_ctrl->use_mdr = 1;

                fsl_elbc_run_command(mtd);
                return;

        /* SEQIN sets up the addr buffer and all registers except the length */
        case NAND_CMD_SEQIN: {
                __be32 fcr;
                dev_vdbg(priv->dev,
                         "fsl_elbc_cmdfunc: NAND_CMD_SEQIN/PAGE_PROG, "
                         "page_addr: 0x%x, column: 0x%x.\n",
                         page_addr, column);

                elbc_fcm_ctrl->column = column;
                elbc_fcm_ctrl->use_mdr = 1;

                if (column >= mtd->writesize) {
                        /* OOB area */
                        column -= mtd->writesize;
                        elbc_fcm_ctrl->oob = 1;
                } else {
                        WARN_ON(column != 0);
                        elbc_fcm_ctrl->oob = 0;
                }

                fcr = (NAND_CMD_STATUS   << FCR_CMD1_SHIFT) |
                      (NAND_CMD_SEQIN    << FCR_CMD2_SHIFT) |
                      (NAND_CMD_PAGEPROG << FCR_CMD3_SHIFT);

                if (priv->page_size) {
                        out_be32(&lbc->fir,
                                 (FIR_OP_CM2 << FIR_OP0_SHIFT) |
                                 (FIR_OP_CA  << FIR_OP1_SHIFT) |
                                 (FIR_OP_PA  << FIR_OP2_SHIFT) |
                                 (FIR_OP_WB  << FIR_OP3_SHIFT) |
                                 (FIR_OP_CM3 << FIR_OP4_SHIFT) |
                                 (FIR_OP_CW1 << FIR_OP5_SHIFT) |
                                 (FIR_OP_RS  << FIR_OP6_SHIFT));
                } else {
                        out_be32(&lbc->fir,
                                 (FIR_OP_CM0 << FIR_OP0_SHIFT) |
                                 (FIR_OP_CM2 << FIR_OP1_SHIFT) |
                                 (FIR_OP_CA  << FIR_OP2_SHIFT) |
                                 (FIR_OP_PA  << FIR_OP3_SHIFT) |
                                 (FIR_OP_WB  << FIR_OP4_SHIFT) |
                                 (FIR_OP_CM3 << FIR_OP5_SHIFT) |
                                 (FIR_OP_CW1 << FIR_OP6_SHIFT) |
                                 (FIR_OP_RS  << FIR_OP7_SHIFT));

                        if (elbc_fcm_ctrl->oob)
                                /* OOB area --> READOOB */
                                fcr |= NAND_CMD_READOOB << FCR_CMD0_SHIFT;
                        else
                                /* First 256 bytes --> READ0 */
                                fcr |= NAND_CMD_READ0 << FCR_CMD0_SHIFT;
                }

                out_be32(&lbc->fcr, fcr);
                set_addr(mtd, column, page_addr, elbc_fcm_ctrl->oob);
                return;
        }

        /* PAGEPROG reuses all of the setup from SEQIN and adds the length */
        case NAND_CMD_PAGEPROG: {
                dev_vdbg(priv->dev,
                         "fsl_elbc_cmdfunc: NAND_CMD_PAGEPROG "
                         "writing %d bytes.\n", elbc_fcm_ctrl->index);

                /* if the write did not start at 0 or is not a full page
                 * then set the exact length, otherwise use a full page
                 * write so the HW generates the ECC.
                 */
                if (elbc_fcm_ctrl->oob || elbc_fcm_ctrl->column != 0 ||
                    elbc_fcm_ctrl->index != mtd->writesize + mtd->oobsize)
                        out_be32(&lbc->fbcr,
                                elbc_fcm_ctrl->index - elbc_fcm_ctrl->column);
                else
                        out_be32(&lbc->fbcr, 0);

                fsl_elbc_run_command(mtd);
                return;
        }

        /* CMD_STATUS must read the status byte while CEB is active */
        /* Note - it does not wait for the ready line */
        case NAND_CMD_STATUS:
                out_be32(&lbc->fir,
                         (FIR_OP_CM0 << FIR_OP0_SHIFT) |
                         (FIR_OP_RBW << FIR_OP1_SHIFT));
                out_be32(&lbc->fcr, NAND_CMD_STATUS << FCR_CMD0_SHIFT);
                out_be32(&lbc->fbcr, 1);
                set_addr(mtd, 0, 0, 0);
                elbc_fcm_ctrl->read_bytes = 1;

                fsl_elbc_run_command(mtd);

                /* The chip always seems to report that it is
                 * write-protected, even when it is not.
                 */
                setbits8(elbc_fcm_ctrl->addr, NAND_STATUS_WP);
                return;

        /* RESET without waiting for the ready line */
        case NAND_CMD_RESET:
                dev_dbg(priv->dev, "fsl_elbc_cmdfunc: NAND_CMD_RESET.\n");
                out_be32(&lbc->fir, FIR_OP_CM0 << FIR_OP0_SHIFT);
                out_be32(&lbc->fcr, NAND_CMD_RESET << FCR_CMD0_SHIFT);
                fsl_elbc_run_command(mtd);
                return;

        default:
                dev_err(priv->dev,
                        "fsl_elbc_cmdfunc: error, unsupported command 0x%x.\n",
                        command);
        }
}

static void fsl_elbc_select_chip(struct mtd_info *mtd, int chip)
{
        /* The hardware does not seem to support multiple
         * chips per bank.
         */
}

/*
 * Write buf to the FCM Controller Data Buffer
 */
static void fsl_elbc_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = priv->ctrl->nand;
        unsigned int bufsize = mtd->writesize + mtd->oobsize;

        if (len <= 0) {
                dev_err(priv->dev, "write_buf of %d bytes", len);
                elbc_fcm_ctrl->status = 0;
                return;
        }

        if ((unsigned int)len > bufsize - elbc_fcm_ctrl->index) {
                dev_err(priv->dev,
                        "write_buf beyond end of buffer "
                        "(%d requested, %u available)\n",
                        len, bufsize - elbc_fcm_ctrl->index);
                len = bufsize - elbc_fcm_ctrl->index;
        }

        memcpy_toio(&elbc_fcm_ctrl->addr[elbc_fcm_ctrl->index], buf, len);
        /*
         * This is workaround for the weird elbc hangs during nand write,
         * Scott Wood says: "...perhaps difference in how long it takes a
         * write to make it through the localbus compared to a write to IMMR
         * is causing problems, and sync isn't helping for some reason."
         * Reading back the last byte helps though.
         */
        in_8(&elbc_fcm_ctrl->addr[elbc_fcm_ctrl->index] + len - 1);

        elbc_fcm_ctrl->index += len;
}

/*
 * read a byte from either the FCM hardware buffer if it has any data left
 * otherwise issue a command to read a single byte.
 */
static u8 fsl_elbc_read_byte(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = priv->ctrl->nand;

        /* If there are still bytes in the FCM, then use the next byte. */
        if (elbc_fcm_ctrl->index < elbc_fcm_ctrl->read_bytes)
                return in_8(&elbc_fcm_ctrl->addr[elbc_fcm_ctrl->index++]);

        dev_err(priv->dev, "read_byte beyond end of buffer\n");
        return ERR_BYTE;
}

/*
 * Read from the FCM Controller Data Buffer
 */
static void fsl_elbc_read_buf(struct mtd_info *mtd, u8 *buf, int len)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = priv->ctrl->nand;
        int avail;

        if (len < 0)
                return;

        avail = min((unsigned int)len,
                        elbc_fcm_ctrl->read_bytes - elbc_fcm_ctrl->index);
        memcpy_fromio(buf, &elbc_fcm_ctrl->addr[elbc_fcm_ctrl->index], avail);
        elbc_fcm_ctrl->index += avail;

        if (len > avail)
                dev_err(priv->dev,
                        "read_buf beyond end of buffer "
                        "(%d requested, %d available)\n",
                        len, avail);
}

/* This function is called after Program and Erase Operations to
 * check for success or failure.
 */
static int fsl_elbc_wait(struct mtd_info *mtd, struct nand_chip *chip)
{
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = priv->ctrl->nand;

        if (elbc_fcm_ctrl->status != LTESR_CC)
                return NAND_STATUS_FAIL;

        /* The chip always seems to report that it is
         * write-protected, even when it is not.
         */
        return (elbc_fcm_ctrl->mdr & 0xff) | NAND_STATUS_WP;
}

static int fsl_elbc_chip_init_tail(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_lbc_ctrl *ctrl = priv->ctrl;
        struct fsl_lbc_regs __iomem *lbc = ctrl->regs;
        unsigned int al;

        /* calculate FMR Address Length field */
        al = 0;
        if (chip->pagemask & 0xffff0000)
                al++;
        if (chip->pagemask & 0xff000000)
                al++;

        priv->fmr |= al << FMR_AL_SHIFT;

        dev_dbg(priv->dev, "fsl_elbc_init: nand->numchips = %d\n",
                chip->numchips);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->chipsize = %lld\n",
                chip->chipsize);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->pagemask = %8x\n",
                chip->pagemask);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->chip_delay = %d\n",
                chip->chip_delay);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->badblockpos = %d\n",
                chip->badblockpos);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->chip_shift = %d\n",
                chip->chip_shift);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->page_shift = %d\n",
                chip->page_shift);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->phys_erase_shift = %d\n",
                chip->phys_erase_shift);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->ecc.mode = %d\n",
                chip->ecc.mode);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->ecc.steps = %d\n",
                chip->ecc.steps);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->ecc.bytes = %d\n",
                chip->ecc.bytes);
        dev_dbg(priv->dev, "fsl_elbc_init: nand->ecc.total = %d\n",
                chip->ecc.total);
        dev_dbg(priv->dev, "fsl_elbc_init: mtd->ooblayout = %p\n",
                mtd->ooblayout);
        dev_dbg(priv->dev, "fsl_elbc_init: mtd->flags = %08x\n", mtd->flags);
        dev_dbg(priv->dev, "fsl_elbc_init: mtd->size = %lld\n", mtd->size);
        dev_dbg(priv->dev, "fsl_elbc_init: mtd->erasesize = %d\n",
                mtd->erasesize);
        dev_dbg(priv->dev, "fsl_elbc_init: mtd->writesize = %d\n",
                mtd->writesize);
        dev_dbg(priv->dev, "fsl_elbc_init: mtd->oobsize = %d\n",
                mtd->oobsize);

        /* adjust Option Register and ECC to match Flash page size */
        if (mtd->writesize == 512) {
                priv->page_size = 0;
                clrbits32(&lbc->bank[priv->bank].or, OR_FCM_PGS);
        } else if (mtd->writesize == 2048) {
                priv->page_size = 1;
                setbits32(&lbc->bank[priv->bank].or, OR_FCM_PGS);
        } else {
                dev_err(priv->dev,
                        "fsl_elbc_init: page size %d is not supported\n",
                        mtd->writesize);
                return -1;
        }

        return 0;
}

static int fsl_elbc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
                              uint8_t *buf, int oob_required, int page)
{
        struct fsl_elbc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_lbc_ctrl *ctrl = priv->ctrl;
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = ctrl->nand;

        fsl_elbc_read_buf(mtd, buf, mtd->writesize);
        if (oob_required)
                fsl_elbc_read_buf(mtd, chip->oob_poi, mtd->oobsize);

        if (fsl_elbc_wait(mtd, chip) & NAND_STATUS_FAIL)
                mtd->ecc_stats.failed++;

        return elbc_fcm_ctrl->max_bitflips;
}

/* ECC will be calculated automatically, and errors will be detected in
 * waitfunc.
 */
static int fsl_elbc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
                                const uint8_t *buf, int oob_required, int page)
{
        fsl_elbc_write_buf(mtd, buf, mtd->writesize);
        fsl_elbc_write_buf(mtd, chip->oob_poi, mtd->oobsize);

        return 0;
}

/* ECC will be calculated automatically, and errors will be detected in
 * waitfunc.
 */
static int fsl_elbc_write_subpage(struct mtd_info *mtd, struct nand_chip *chip,
                                uint32_t offset, uint32_t data_len,
                                const uint8_t *buf, int oob_required, int page)
{
        fsl_elbc_write_buf(mtd, buf, mtd->writesize);
        fsl_elbc_write_buf(mtd, chip->oob_poi, mtd->oobsize);

        return 0;
}

static int fsl_elbc_chip_init(struct fsl_elbc_mtd *priv)
{
        struct fsl_lbc_ctrl *ctrl = priv->ctrl;
        struct fsl_lbc_regs __iomem *lbc = ctrl->regs;
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = ctrl->nand;
        struct nand_chip *chip = &priv->chip;
        struct mtd_info *mtd = nand_to_mtd(chip);

        dev_dbg(priv->dev, "eLBC Set Information for bank %d\n", priv->bank);

        /* Fill in fsl_elbc_mtd structure */
        mtd->dev.parent = priv->dev;
        nand_set_flash_node(chip, priv->dev->of_node);

        /* set timeout to maximum */
        priv->fmr = 15 << FMR_CWTO_SHIFT;
        if (in_be32(&lbc->bank[priv->bank].or) & OR_FCM_PGS)
                priv->fmr |= FMR_ECCM;

        /* fill in nand_chip structure */
        /* set up function call table */
        chip->read_byte = fsl_elbc_read_byte;
        chip->write_buf = fsl_elbc_write_buf;
        chip->read_buf = fsl_elbc_read_buf;
        chip->select_chip = fsl_elbc_select_chip;
        chip->cmdfunc = fsl_elbc_cmdfunc;
        chip->waitfunc = fsl_elbc_wait;

        chip->bbt_td = &bbt_main_descr;
        chip->bbt_md = &bbt_mirror_descr;

        /* set up nand options */
        chip->bbt_options = NAND_BBT_USE_FLASH;

        chip->controller = &elbc_fcm_ctrl->controller;
        nand_set_controller_data(chip, priv);

        chip->ecc.read_page = fsl_elbc_read_page;
        chip->ecc.write_page = fsl_elbc_write_page;
        chip->ecc.write_subpage = fsl_elbc_write_subpage;

        /* If CS Base Register selects full hardware ECC then use it */
        if ((in_be32(&lbc->bank[priv->bank].br) & BR_DECC) ==
            BR_DECC_CHK_GEN) {
                chip->ecc.mode = NAND_ECC_HW;
                mtd_set_ooblayout(mtd, &fsl_elbc_ooblayout_ops);
                chip->ecc.size = 512;
                chip->ecc.bytes = 3;
                chip->ecc.strength = 1;
        } else {
                /* otherwise fall back to default software ECC */
                chip->ecc.mode = NAND_ECC_SOFT;
                chip->ecc.algo = NAND_ECC_HAMMING;
        }

        return 0;
}

static int fsl_elbc_chip_remove(struct fsl_elbc_mtd *priv)
{
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = priv->ctrl->nand;
        struct mtd_info *mtd = nand_to_mtd(&priv->chip);

        nand_release(mtd);

        kfree(mtd->name);

        if (priv->vbase)
                iounmap(priv->vbase);

        elbc_fcm_ctrl->chips[priv->bank] = NULL;
        kfree(priv);
        return 0;
}

static DEFINE_MUTEX(fsl_elbc_nand_mutex);

static int fsl_elbc_nand_probe(struct platform_device *pdev)
{
        struct fsl_lbc_regs __iomem *lbc;
        struct fsl_elbc_mtd *priv;
        struct resource res;
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl;
        static const char *part_probe_types[]
                = { "cmdlinepart", "RedBoot", "ofpart", NULL };
        int ret;
        int bank;
        struct device *dev;
        struct device_node *node = pdev->dev.of_node;
        struct mtd_info *mtd;

        if (!fsl_lbc_ctrl_dev || !fsl_lbc_ctrl_dev->regs)
                return -ENODEV;
        lbc = fsl_lbc_ctrl_dev->regs;
        dev = fsl_lbc_ctrl_dev->dev;

        /* get, allocate and map the memory resource */
        ret = of_address_to_resource(node, 0, &res);
        if (ret) {
                dev_err(dev, "failed to get resource\n");
                return ret;
        }

        /* find which chip select it is connected to */
        for (bank = 0; bank < MAX_BANKS; bank++)
                if ((in_be32(&lbc->bank[bank].br) & BR_V) &&
                    (in_be32(&lbc->bank[bank].br) & BR_MSEL) == BR_MS_FCM &&
                    (in_be32(&lbc->bank[bank].br) &
                     in_be32(&lbc->bank[bank].or) & BR_BA)
                     == fsl_lbc_addr(res.start))
                        break;

        if (bank >= MAX_BANKS) {
                dev_err(dev, "address did not match any chip selects\n");
                return -ENODEV;
        }

        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        mutex_lock(&fsl_elbc_nand_mutex);
        if (!fsl_lbc_ctrl_dev->nand) {
                elbc_fcm_ctrl = kzalloc(sizeof(*elbc_fcm_ctrl), GFP_KERNEL);
                if (!elbc_fcm_ctrl) {
                        mutex_unlock(&fsl_elbc_nand_mutex);
                        ret = -ENOMEM;
                        goto err;
                }
                elbc_fcm_ctrl->counter++;

                nand_hw_control_init(&elbc_fcm_ctrl->controller);
                fsl_lbc_ctrl_dev->nand = elbc_fcm_ctrl;
        } else {
                elbc_fcm_ctrl = fsl_lbc_ctrl_dev->nand;
        }
        mutex_unlock(&fsl_elbc_nand_mutex);

        elbc_fcm_ctrl->chips[bank] = priv;
        priv->bank = bank;
        priv->ctrl = fsl_lbc_ctrl_dev;
        priv->dev = &pdev->dev;
        dev_set_drvdata(priv->dev, priv);

        priv->vbase = ioremap(res.start, resource_size(&res));
        if (!priv->vbase) {
                dev_err(dev, "failed to map chip region\n");
                ret = -ENOMEM;
                goto err;
        }

        mtd = nand_to_mtd(&priv->chip);
        mtd->name = kasprintf(GFP_KERNEL, "%llx.flash", (u64)res.start);
        if (!nand_to_mtd(&priv->chip)->name) {
                ret = -ENOMEM;
                goto err;
        }

        ret = fsl_elbc_chip_init(priv);
        if (ret)
                goto err;

        ret = nand_scan_ident(mtd, 1, NULL);
        if (ret)
                goto err;

        ret = fsl_elbc_chip_init_tail(mtd);
        if (ret)
                goto err;

        ret = nand_scan_tail(mtd);
        if (ret)
                goto err;

        /* First look for RedBoot table or partitions on the command
         * line, these take precedence over device tree information */
        mtd_device_parse_register(mtd, part_probe_types, NULL,
                                  NULL, 0);

        printk(KERN_INFO "eLBC NAND device at 0x%llx, bank %d\n",
               (unsigned long long)res.start, priv->bank);
        return 0;

err:
        fsl_elbc_chip_remove(priv);
        return ret;
}

static int fsl_elbc_nand_remove(struct platform_device *pdev)
{
        struct fsl_elbc_fcm_ctrl *elbc_fcm_ctrl = fsl_lbc_ctrl_dev->nand;
        struct fsl_elbc_mtd *priv = dev_get_drvdata(&pdev->dev);

        fsl_elbc_chip_remove(priv);

        mutex_lock(&fsl_elbc_nand_mutex);
        elbc_fcm_ctrl->counter--;
        if (!elbc_fcm_ctrl->counter) {
                fsl_lbc_ctrl_dev->nand = NULL;
                kfree(elbc_fcm_ctrl);
        }
        mutex_unlock(&fsl_elbc_nand_mutex);

        return 0;

}

static const struct of_device_id fsl_elbc_nand_match[] = {
        { .compatible = "fsl,elbc-fcm-nand", },
        {}
};
MODULE_DEVICE_TABLE(of, fsl_elbc_nand_match);

static struct platform_driver fsl_elbc_nand_driver = {
        .driver = {
                .name = "fsl,elbc-fcm-nand",
                .of_match_table = fsl_elbc_nand_match,
        },
        .probe = fsl_elbc_nand_probe,
        .remove = fsl_elbc_nand_remove,
};

module_platform_driver(fsl_elbc_nand_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Freescale");
MODULE_DESCRIPTION("Freescale Enhanced Local Bus Controller MTD NAND driver");