/*
 * Freescale Integrated Flash Controller NAND driver
 *
 * Copyright 2011-2012 Freescale Semiconductor, Inc
 *
 * Author: Dipen Dudhat <Dipen.Dudhat@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/of_address.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/nand_ecc.h>
#include <linux/fsl_ifc.h>

#define ERR_BYTE                0xFF /* Value returned for read
                                        bytes when read failed  */
#define IFC_TIMEOUT_MSECS       500  /* Maximum number of mSecs to wait
                                        for IFC NAND Machine    */

struct fsl_ifc_ctrl;

/* mtd information per set */
struct fsl_ifc_mtd {
        struct nand_chip chip;
        struct fsl_ifc_ctrl *ctrl;

        struct device *dev;
        int bank;               /* Chip select bank number              */
        unsigned int bufnum_mask; /* bufnum = page & bufnum_mask */
        u8 __iomem *vbase;      /* Chip select base virtual address     */
};

/* overview of the fsl ifc controller */
struct fsl_ifc_nand_ctrl {
        struct nand_hw_control controller;
        struct fsl_ifc_mtd *chips[FSL_IFC_BANK_COUNT];

        void __iomem *addr;     /* Address of assigned IFC 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 oob;       /* Non zero if operating on OOB data    */
        unsigned int eccread;   /* Non zero for a full-page ECC read    */
        unsigned int counter;   /* counter for the initializations      */
        unsigned int max_bitflips;  /* Saved during READ0 cmd           */
};

static struct fsl_ifc_nand_ctrl *ifc_nand_ctrl;

/*
 * Generic flash bbt descriptors
 */
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 = 2, /* 0 on 8-bit small page */
        .len = 4,
        .veroffs = 6,
        .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 = 2, /* 0 on 8-bit small page */
        .len = 4,
        .veroffs = 6,
        .maxblocks = 4,
        .pattern = mirror_pattern,
};

static int fsl_ifc_ooblayout_ecc(struct mtd_info *mtd, int section,
                                 struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);

        if (section)
                return -ERANGE;

        oobregion->offset = 8;
        oobregion->length = chip->ecc.total;

        return 0;
}

static int fsl_ifc_ooblayout_free(struct mtd_info *mtd, int section,
                                  struct mtd_oob_region *oobregion)
{
        struct nand_chip *chip = mtd_to_nand(mtd);

        if (section > 1)
                return -ERANGE;

        if (mtd->writesize == 512 &&
            !(chip->options & NAND_BUSWIDTH_16)) {
                if (!section) {
                        oobregion->offset = 0;
                        oobregion->length = 5;
                } else {
                        oobregion->offset = 6;
                        oobregion->length = 2;
                }

                return 0;
        }

        if (!section) {
                oobregion->offset = 2;
                oobregion->length = 6;
        } else {
                oobregion->offset = chip->ecc.total + 8;
                oobregion->length = mtd->oobsize - oobregion->offset;
        }

        return 0;
}

static const struct mtd_ooblayout_ops fsl_ifc_ooblayout_ops = {
        .ecc = fsl_ifc_ooblayout_ecc,
        .free = fsl_ifc_ooblayout_free,
};

/*
 * Set up the IFC hardware block and page address fields, and the ifc nand
 * structure addr field to point to the correct IFC 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_ifc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_ifc_ctrl *ctrl = priv->ctrl;
        struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;
        int buf_num;

        ifc_nand_ctrl->page = page_addr;
        /* Program ROW0/COL0 */
        ifc_out32(page_addr, &ifc->ifc_nand.row0);
        ifc_out32((oob ? IFC_NAND_COL_MS : 0) | column, &ifc->ifc_nand.col0);

        buf_num = page_addr & priv->bufnum_mask;

        ifc_nand_ctrl->addr = priv->vbase + buf_num * (mtd->writesize * 2);
        ifc_nand_ctrl->index = column;

        /* for OOB data point to the second half of the buffer */
        if (oob)
                ifc_nand_ctrl->index += mtd->writesize;
}

/* returns nonzero if entire page is blank */
static int check_read_ecc(struct mtd_info *mtd, struct fsl_ifc_ctrl *ctrl,
                          u32 eccstat, unsigned int bufnum)
{
        return  (eccstat >> ((3 - bufnum % 4) * 8)) & 15;
}

/*
 * execute IFC NAND command and wait for it to complete
 */
static void fsl_ifc_run_command(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_ifc_ctrl *ctrl = priv->ctrl;
        struct fsl_ifc_nand_ctrl *nctrl = ifc_nand_ctrl;
        struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;
        u32 eccstat;
        int i;

        /* set the chip select for NAND Transaction */
        ifc_out32(priv->bank << IFC_NAND_CSEL_SHIFT,
                  &ifc->ifc_nand.nand_csel);

        dev_vdbg(priv->dev,
                        "%s: fir0=%08x fcr0=%08x\n",
                        __func__,
                        ifc_in32(&ifc->ifc_nand.nand_fir0),
                        ifc_in32(&ifc->ifc_nand.nand_fcr0));

        ctrl->nand_stat = 0;

        /* start read/write seq */
        ifc_out32(IFC_NAND_SEQ_STRT_FIR_STRT, &ifc->ifc_nand.nandseq_strt);

        /* wait for command complete flag or timeout */
        wait_event_timeout(ctrl->nand_wait, ctrl->nand_stat,
                           msecs_to_jiffies(IFC_TIMEOUT_MSECS));

        /* ctrl->nand_stat will be updated from IRQ context */
        if (!ctrl->nand_stat)
                dev_err(priv->dev, "Controller is not responding\n");
        if (ctrl->nand_stat & IFC_NAND_EVTER_STAT_FTOER)
                dev_err(priv->dev, "NAND Flash Timeout Error\n");
        if (ctrl->nand_stat & IFC_NAND_EVTER_STAT_WPER)
                dev_err(priv->dev, "NAND Flash Write Protect Error\n");

        nctrl->max_bitflips = 0;

        if (nctrl->eccread) {
                int errors;
                int bufnum = nctrl->page & priv->bufnum_mask;
                int sector_start = bufnum * chip->ecc.steps;
                int sector_end = sector_start + chip->ecc.steps - 1;
                __be32 *eccstat_regs;

                eccstat_regs = ifc->ifc_nand.nand_eccstat;
                eccstat = ifc_in32(&eccstat_regs[sector_start / 4]);

                for (i = sector_start; i <= sector_end; i++) {
                        if (i != sector_start && !(i % 4))
                                eccstat = ifc_in32(&eccstat_regs[i / 4]);

                        errors = check_read_ecc(mtd, ctrl, eccstat, i);

                        if (errors == 15) {
                                /*
                                 * Uncorrectable error.
                                 * We'll check for blank pages later.
                                 *
                                 * We disable ECCER reporting due to...
                                 * erratum IFC-A002770 -- so report it now if we
                                 * see an uncorrectable error in ECCSTAT.
                                 */
                                ctrl->nand_stat |= IFC_NAND_EVTER_STAT_ECCER;
                                continue;
                        }

                        mtd->ecc_stats.corrected += errors;
                        nctrl->max_bitflips = max_t(unsigned int,
                                                    nctrl->max_bitflips,
                                                    errors);
                }

                nctrl->eccread = 0;
        }
}

static void fsl_ifc_do_read(struct nand_chip *chip,
                            int oob,
                            struct mtd_info *mtd)
{
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_ifc_ctrl *ctrl = priv->ctrl;
        struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;

        /* Program FIR/IFC_NAND_FCR0 for Small/Large page */
        if (mtd->writesize > 512) {
                ifc_out32((IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                          (IFC_FIR_OP_CA0 << IFC_NAND_FIR0_OP1_SHIFT) |
                          (IFC_FIR_OP_RA0 << IFC_NAND_FIR0_OP2_SHIFT) |
                          (IFC_FIR_OP_CMD1 << IFC_NAND_FIR0_OP3_SHIFT) |
                          (IFC_FIR_OP_RBCD << IFC_NAND_FIR0_OP4_SHIFT),
                          &ifc->ifc_nand.nand_fir0);
                ifc_out32(0x0, &ifc->ifc_nand.nand_fir1);

                ifc_out32((NAND_CMD_READ0 << IFC_NAND_FCR0_CMD0_SHIFT) |
                          (NAND_CMD_READSTART << IFC_NAND_FCR0_CMD1_SHIFT),
                          &ifc->ifc_nand.nand_fcr0);
        } else {
                ifc_out32((IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                          (IFC_FIR_OP_CA0 << IFC_NAND_FIR0_OP1_SHIFT) |
                          (IFC_FIR_OP_RA0  << IFC_NAND_FIR0_OP2_SHIFT) |
                          (IFC_FIR_OP_RBCD << IFC_NAND_FIR0_OP3_SHIFT),
                          &ifc->ifc_nand.nand_fir0);
                ifc_out32(0x0, &ifc->ifc_nand.nand_fir1);

                if (oob)
                        ifc_out32(NAND_CMD_READOOB <<
                                  IFC_NAND_FCR0_CMD0_SHIFT,
                                  &ifc->ifc_nand.nand_fcr0);
                else
                        ifc_out32(NAND_CMD_READ0 <<
                                  IFC_NAND_FCR0_CMD0_SHIFT,
                                  &ifc->ifc_nand.nand_fcr0);
        }
}

/* cmdfunc send commands to the IFC NAND Machine */
static void fsl_ifc_cmdfunc(struct mtd_info *mtd, unsigned int command,
                             int column, int page_addr) {
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_ifc_ctrl *ctrl = priv->ctrl;
        struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;

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

        switch (command) {
        /* READ0 read the entire buffer to use hardware ECC. */
        case NAND_CMD_READ0:
                ifc_out32(0, &ifc->ifc_nand.nand_fbcr);
                set_addr(mtd, 0, page_addr, 0);

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

                if (chip->ecc.mode == NAND_ECC_HW)
                        ifc_nand_ctrl->eccread = 1;

                fsl_ifc_do_read(chip, 0, mtd);
                fsl_ifc_run_command(mtd);
                return;

        /* READOOB reads only the OOB because no ECC is performed. */
        case NAND_CMD_READOOB:
                ifc_out32(mtd->oobsize - column, &ifc->ifc_nand.nand_fbcr);
                set_addr(mtd, column, page_addr, 1);

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

                fsl_ifc_do_read(chip, 1, mtd);
                fsl_ifc_run_command(mtd);

                return;

        case NAND_CMD_READID:
        case NAND_CMD_PARAM: {
                int timing = IFC_FIR_OP_RB;
                if (command == NAND_CMD_PARAM)
                        timing = IFC_FIR_OP_RBCD;

                ifc_out32((IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                          (IFC_FIR_OP_UA  << IFC_NAND_FIR0_OP1_SHIFT) |
                          (timing << IFC_NAND_FIR0_OP2_SHIFT),
                          &ifc->ifc_nand.nand_fir0);
                ifc_out32(command << IFC_NAND_FCR0_CMD0_SHIFT,
                          &ifc->ifc_nand.nand_fcr0);
                ifc_out32(column, &ifc->ifc_nand.row3);

                /*
                 * although currently it's 8 bytes for READID, we always read
                 * the maximum 256 bytes(for PARAM)
                 */
                ifc_out32(256, &ifc->ifc_nand.nand_fbcr);
                ifc_nand_ctrl->read_bytes = 256;

                set_addr(mtd, 0, 0, 0);
                fsl_ifc_run_command(mtd);
                return;
        }

        /* ERASE1 stores the block and page address */
        case NAND_CMD_ERASE1:
                set_addr(mtd, 0, page_addr, 0);
                return;

        /* ERASE2 uses the block and page address from ERASE1 */
        case NAND_CMD_ERASE2:
                ifc_out32((IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                          (IFC_FIR_OP_RA0 << IFC_NAND_FIR0_OP1_SHIFT) |
                          (IFC_FIR_OP_CMD1 << IFC_NAND_FIR0_OP2_SHIFT),
                          &ifc->ifc_nand.nand_fir0);

                ifc_out32((NAND_CMD_ERASE1 << IFC_NAND_FCR0_CMD0_SHIFT) |
                          (NAND_CMD_ERASE2 << IFC_NAND_FCR0_CMD1_SHIFT),
                          &ifc->ifc_nand.nand_fcr0);

                ifc_out32(0, &ifc->ifc_nand.nand_fbcr);
                ifc_nand_ctrl->read_bytes = 0;
                fsl_ifc_run_command(mtd);
                return;

        /* SEQIN sets up the addr buffer and all registers except the length */
        case NAND_CMD_SEQIN: {
                u32 nand_fcr0;
                ifc_nand_ctrl->column = column;
                ifc_nand_ctrl->oob = 0;

                if (mtd->writesize > 512) {
                        nand_fcr0 =
                                (NAND_CMD_SEQIN << IFC_NAND_FCR0_CMD0_SHIFT) |
                                (NAND_CMD_STATUS << IFC_NAND_FCR0_CMD1_SHIFT) |
                                (NAND_CMD_PAGEPROG << IFC_NAND_FCR0_CMD2_SHIFT);

                        ifc_out32(
                                (IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                                (IFC_FIR_OP_CA0 << IFC_NAND_FIR0_OP1_SHIFT) |
                                (IFC_FIR_OP_RA0 << IFC_NAND_FIR0_OP2_SHIFT) |
                                (IFC_FIR_OP_WBCD << IFC_NAND_FIR0_OP3_SHIFT) |
                                (IFC_FIR_OP_CMD2 << IFC_NAND_FIR0_OP4_SHIFT),
                                &ifc->ifc_nand.nand_fir0);
                        ifc_out32(
                                (IFC_FIR_OP_CW1 << IFC_NAND_FIR1_OP5_SHIFT) |
                                (IFC_FIR_OP_RDSTAT << IFC_NAND_FIR1_OP6_SHIFT) |
                                (IFC_FIR_OP_NOP << IFC_NAND_FIR1_OP7_SHIFT),
                                &ifc->ifc_nand.nand_fir1);
                } else {
                        nand_fcr0 = ((NAND_CMD_PAGEPROG <<
                                        IFC_NAND_FCR0_CMD1_SHIFT) |
                                    (NAND_CMD_SEQIN <<
                                        IFC_NAND_FCR0_CMD2_SHIFT) |
                                    (NAND_CMD_STATUS <<
                                        IFC_NAND_FCR0_CMD3_SHIFT));

                        ifc_out32(
                                (IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                                (IFC_FIR_OP_CMD2 << IFC_NAND_FIR0_OP1_SHIFT) |
                                (IFC_FIR_OP_CA0 << IFC_NAND_FIR0_OP2_SHIFT) |
                                (IFC_FIR_OP_RA0 << IFC_NAND_FIR0_OP3_SHIFT) |
                                (IFC_FIR_OP_WBCD << IFC_NAND_FIR0_OP4_SHIFT),
                                &ifc->ifc_nand.nand_fir0);
                        ifc_out32(
                                (IFC_FIR_OP_CMD1 << IFC_NAND_FIR1_OP5_SHIFT) |
                                (IFC_FIR_OP_CW3 << IFC_NAND_FIR1_OP6_SHIFT) |
                                (IFC_FIR_OP_RDSTAT << IFC_NAND_FIR1_OP7_SHIFT) |
                                (IFC_FIR_OP_NOP << IFC_NAND_FIR1_OP8_SHIFT),
                                &ifc->ifc_nand.nand_fir1);

                        if (column >= mtd->writesize)
                                nand_fcr0 |=
                                NAND_CMD_READOOB << IFC_NAND_FCR0_CMD0_SHIFT;
                        else
                                nand_fcr0 |=
                                NAND_CMD_READ0 << IFC_NAND_FCR0_CMD0_SHIFT;
                }

                if (column >= mtd->writesize) {
                        /* OOB area --> READOOB */
                        column -= mtd->writesize;
                        ifc_nand_ctrl->oob = 1;
                }
                ifc_out32(nand_fcr0, &ifc->ifc_nand.nand_fcr0);
                set_addr(mtd, column, page_addr, ifc_nand_ctrl->oob);
                return;
        }

        /* PAGEPROG reuses all of the setup from SEQIN and adds the length */
        case NAND_CMD_PAGEPROG: {
                if (ifc_nand_ctrl->oob) {
                        ifc_out32(ifc_nand_ctrl->index -
                                  ifc_nand_ctrl->column,
                                  &ifc->ifc_nand.nand_fbcr);
                } else {
                        ifc_out32(0, &ifc->ifc_nand.nand_fbcr);
                }

                fsl_ifc_run_command(mtd);
                return;
        }

        case NAND_CMD_STATUS: {
                void __iomem *addr;

                ifc_out32((IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                          (IFC_FIR_OP_RB << IFC_NAND_FIR0_OP1_SHIFT),
                          &ifc->ifc_nand.nand_fir0);
                ifc_out32(NAND_CMD_STATUS << IFC_NAND_FCR0_CMD0_SHIFT,
                          &ifc->ifc_nand.nand_fcr0);
                ifc_out32(1, &ifc->ifc_nand.nand_fbcr);
                set_addr(mtd, 0, 0, 0);
                ifc_nand_ctrl->read_bytes = 1;

                fsl_ifc_run_command(mtd);

                /*
                 * The chip always seems to report that it is
                 * write-protected, even when it is not.
                 */
                addr = ifc_nand_ctrl->addr;
                if (chip->options & NAND_BUSWIDTH_16)
                        ifc_out16(ifc_in16(addr) | (NAND_STATUS_WP), addr);
                else
                        ifc_out8(ifc_in8(addr) | (NAND_STATUS_WP), addr);
                return;
        }

        case NAND_CMD_RESET:
                ifc_out32(IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT,
                          &ifc->ifc_nand.nand_fir0);
                ifc_out32(NAND_CMD_RESET << IFC_NAND_FCR0_CMD0_SHIFT,
                          &ifc->ifc_nand.nand_fcr0);
                fsl_ifc_run_command(mtd);
                return;

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

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

/*
 * Write buf to the IFC NAND Controller Data Buffer
 */
static void fsl_ifc_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        unsigned int bufsize = mtd->writesize + mtd->oobsize;

        if (len <= 0) {
                dev_err(priv->dev, "%s: len %d bytes", __func__, len);
                return;
        }

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

        memcpy_toio(ifc_nand_ctrl->addr + ifc_nand_ctrl->index, buf, len);
        ifc_nand_ctrl->index += len;
}

/*
 * Read a byte from either the IFC hardware buffer
 * read function for 8-bit buswidth
 */
static uint8_t fsl_ifc_read_byte(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        unsigned int offset;

        /*
         * If there are still bytes in the IFC buffer, then use the
         * next byte.
         */
        if (ifc_nand_ctrl->index < ifc_nand_ctrl->read_bytes) {
                offset = ifc_nand_ctrl->index++;
                return ifc_in8(ifc_nand_ctrl->addr + offset);
        }

        dev_err(priv->dev, "%s: beyond end of buffer\n", __func__);
        return ERR_BYTE;
}

/*
 * Read two bytes from the IFC hardware buffer
 * read function for 16-bit buswith
 */
static uint8_t fsl_ifc_read_byte16(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        uint16_t data;

        /*
         * If there are still bytes in the IFC buffer, then use the
         * next byte.
         */
        if (ifc_nand_ctrl->index < ifc_nand_ctrl->read_bytes) {
                data = ifc_in16(ifc_nand_ctrl->addr + ifc_nand_ctrl->index);
                ifc_nand_ctrl->index += 2;
                return (uint8_t) data;
        }

        dev_err(priv->dev, "%s: beyond end of buffer\n", __func__);
        return ERR_BYTE;
}

/*
 * Read from the IFC Controller Data Buffer
 */
static void fsl_ifc_read_buf(struct mtd_info *mtd, u8 *buf, int len)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        int avail;

        if (len < 0) {
                dev_err(priv->dev, "%s: len %d bytes", __func__, len);
                return;
        }

        avail = min((unsigned int)len,
                        ifc_nand_ctrl->read_bytes - ifc_nand_ctrl->index);
        memcpy_fromio(buf, ifc_nand_ctrl->addr + ifc_nand_ctrl->index, avail);
        ifc_nand_ctrl->index += avail;

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

/*
 * This function is called after Program and Erase Operations to
 * check for success or failure.
 */
static int fsl_ifc_wait(struct mtd_info *mtd, struct nand_chip *chip)
{
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_ifc_ctrl *ctrl = priv->ctrl;
        struct fsl_ifc_runtime __iomem *ifc = ctrl->rregs;
        u32 nand_fsr;
        int status;

        /* Use READ_STATUS command, but wait for the device to be ready */
        ifc_out32((IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                  (IFC_FIR_OP_RDSTAT << IFC_NAND_FIR0_OP1_SHIFT),
                  &ifc->ifc_nand.nand_fir0);
        ifc_out32(NAND_CMD_STATUS << IFC_NAND_FCR0_CMD0_SHIFT,
                  &ifc->ifc_nand.nand_fcr0);
        ifc_out32(1, &ifc->ifc_nand.nand_fbcr);
        set_addr(mtd, 0, 0, 0);
        ifc_nand_ctrl->read_bytes = 1;

        fsl_ifc_run_command(mtd);

        nand_fsr = ifc_in32(&ifc->ifc_nand.nand_fsr);
        status = nand_fsr >> 24;
        /*
         * The chip always seems to report that it is
         * write-protected, even when it is not.
         */
        return status | NAND_STATUS_WP;
}

/*
 * The controller does not check for bitflips in erased pages,
 * therefore software must check instead.
 */
static int check_erased_page(struct nand_chip *chip, u8 *buf)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        u8 *ecc = chip->oob_poi;
        const int ecc_size = chip->ecc.bytes;
        const int pkt_size = chip->ecc.size;
        int i, res, bitflips = 0;
        struct mtd_oob_region oobregion = { };

        mtd_ooblayout_ecc(mtd, 0, &oobregion);
        ecc += oobregion.offset;

        for (i = 0; i < chip->ecc.steps; ++i) {
                res = nand_check_erased_ecc_chunk(buf, pkt_size, ecc, ecc_size,
                                                  NULL, 0,
                                                  chip->ecc.strength);
                if (res < 0)
                        mtd->ecc_stats.failed++;
                else
                        mtd->ecc_stats.corrected += res;

                bitflips = max(res, bitflips);
                buf += pkt_size;
                ecc += ecc_size;
        }

        return bitflips;
}

static int fsl_ifc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
                             uint8_t *buf, int oob_required, int page)
{
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);
        struct fsl_ifc_ctrl *ctrl = priv->ctrl;
        struct fsl_ifc_nand_ctrl *nctrl = ifc_nand_ctrl;

        nand_read_page_op(chip, page, 0, buf, mtd->writesize);
        if (oob_required)
                fsl_ifc_read_buf(mtd, chip->oob_poi, mtd->oobsize);

        if (ctrl->nand_stat & IFC_NAND_EVTER_STAT_ECCER) {
                if (!oob_required)
                        fsl_ifc_read_buf(mtd, chip->oob_poi, mtd->oobsize);

                return check_erased_page(chip, buf);
        }

        if (ctrl->nand_stat != IFC_NAND_EVTER_STAT_OPC)
                mtd->ecc_stats.failed++;

        return nctrl->max_bitflips;
}

/* ECC will be calculated automatically, and errors will be detected in
 * waitfunc.
 */
static int fsl_ifc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
                               const uint8_t *buf, int oob_required, int page)
{
        nand_prog_page_begin_op(chip, page, 0, buf, mtd->writesize);
        fsl_ifc_write_buf(mtd, chip->oob_poi, mtd->oobsize);

        return nand_prog_page_end_op(chip);
}

static int fsl_ifc_chip_init_tail(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct fsl_ifc_mtd *priv = nand_get_controller_data(chip);

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

        return 0;
}

static void fsl_ifc_sram_init(struct fsl_ifc_mtd *priv)
{
        struct fsl_ifc_ctrl *ctrl = priv->ctrl;
        struct fsl_ifc_runtime __iomem *ifc_runtime = ctrl->rregs;
        struct fsl_ifc_global __iomem *ifc_global = ctrl->gregs;
        uint32_t csor = 0, csor_8k = 0, csor_ext = 0;
        uint32_t cs = priv->bank;

        /* Save CSOR and CSOR_ext */
        csor = ifc_in32(&ifc_global->csor_cs[cs].csor);
        csor_ext = ifc_in32(&ifc_global->csor_cs[cs].csor_ext);

        /* chage PageSize 8K and SpareSize 1K*/
        csor_8k = (csor & ~(CSOR_NAND_PGS_MASK)) | 0x0018C000;
        ifc_out32(csor_8k, &ifc_global->csor_cs[cs].csor);
        ifc_out32(0x0000400, &ifc_global->csor_cs[cs].csor_ext);

        /* READID */
        ifc_out32((IFC_FIR_OP_CW0 << IFC_NAND_FIR0_OP0_SHIFT) |
                    (IFC_FIR_OP_UA  << IFC_NAND_FIR0_OP1_SHIFT) |
                    (IFC_FIR_OP_RB << IFC_NAND_FIR0_OP2_SHIFT),
                    &ifc_runtime->ifc_nand.nand_fir0);
        ifc_out32(NAND_CMD_READID << IFC_NAND_FCR0_CMD0_SHIFT,
                    &ifc_runtime->ifc_nand.nand_fcr0);
        ifc_out32(0x0, &ifc_runtime->ifc_nand.row3);

        ifc_out32(0x0, &ifc_runtime->ifc_nand.nand_fbcr);

        /* Program ROW0/COL0 */
        ifc_out32(0x0, &ifc_runtime->ifc_nand.row0);
        ifc_out32(0x0, &ifc_runtime->ifc_nand.col0);

        /* set the chip select for NAND Transaction */
        ifc_out32(cs << IFC_NAND_CSEL_SHIFT,
                &ifc_runtime->ifc_nand.nand_csel);

        /* start read seq */
        ifc_out32(IFC_NAND_SEQ_STRT_FIR_STRT,
                &ifc_runtime->ifc_nand.nandseq_strt);

        /* wait for command complete flag or timeout */
        wait_event_timeout(ctrl->nand_wait, ctrl->nand_stat,
                           msecs_to_jiffies(IFC_TIMEOUT_MSECS));

        if (ctrl->nand_stat != IFC_NAND_EVTER_STAT_OPC)
                pr_err("fsl-ifc: Failed to Initialise SRAM\n");

        /* Restore CSOR and CSOR_ext */
        ifc_out32(csor, &ifc_global->csor_cs[cs].csor);
        ifc_out32(csor_ext, &ifc_global->csor_cs[cs].csor_ext);
}

static int fsl_ifc_chip_init(struct fsl_ifc_mtd *priv)
{
        struct fsl_ifc_ctrl *ctrl = priv->ctrl;
        struct fsl_ifc_global __iomem *ifc_global = ctrl->gregs;
        struct fsl_ifc_runtime __iomem *ifc_runtime = ctrl->rregs;
        struct nand_chip *chip = &priv->chip;
        struct mtd_info *mtd = nand_to_mtd(&priv->chip);
        u32 csor;

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

        /* fill in nand_chip structure */
        /* set up function call table */
        if ((ifc_in32(&ifc_global->cspr_cs[priv->bank].cspr))
                & CSPR_PORT_SIZE_16)
                chip->read_byte = fsl_ifc_read_byte16;
        else
                chip->read_byte = fsl_ifc_read_byte;

        chip->write_buf = fsl_ifc_write_buf;
        chip->read_buf = fsl_ifc_read_buf;
        chip->select_chip = fsl_ifc_select_chip;
        chip->cmdfunc = fsl_ifc_cmdfunc;
        chip->waitfunc = fsl_ifc_wait;
        chip->set_features = nand_get_set_features_notsupp;
        chip->get_features = nand_get_set_features_notsupp;

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

        ifc_out32(0x0, &ifc_runtime->ifc_nand.ncfgr);

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

        if (ifc_in32(&ifc_global->cspr_cs[priv->bank].cspr)
                & CSPR_PORT_SIZE_16) {
                chip->read_byte = fsl_ifc_read_byte16;
                chip->options |= NAND_BUSWIDTH_16;
        } else {
                chip->read_byte = fsl_ifc_read_byte;
        }

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

        chip->ecc.read_page = fsl_ifc_read_page;
        chip->ecc.write_page = fsl_ifc_write_page;

        csor = ifc_in32(&ifc_global->csor_cs[priv->bank].csor);

        switch (csor & CSOR_NAND_PGS_MASK) {
        case CSOR_NAND_PGS_512:
                if (!(chip->options & NAND_BUSWIDTH_16)) {
                        /* Avoid conflict with bad block marker */
                        bbt_main_descr.offs = 0;
                        bbt_mirror_descr.offs = 0;
                }

                priv->bufnum_mask = 15;
                break;

        case CSOR_NAND_PGS_2K:
                priv->bufnum_mask = 3;
                break;

        case CSOR_NAND_PGS_4K:
                priv->bufnum_mask = 1;
                break;

        case CSOR_NAND_PGS_8K:
                priv->bufnum_mask = 0;
                break;

        default:
                dev_err(priv->dev, "bad csor %#x: bad page size\n", csor);
                return -ENODEV;
        }

        /* Must also set CSOR_NAND_ECC_ENC_EN if DEC_EN set */
        if (csor & CSOR_NAND_ECC_DEC_EN) {
                chip->ecc.mode = NAND_ECC_HW;
                mtd_set_ooblayout(mtd, &fsl_ifc_ooblayout_ops);

                /* Hardware generates ECC per 512 Bytes */
                chip->ecc.size = 512;
                if ((csor & CSOR_NAND_ECC_MODE_MASK) == CSOR_NAND_ECC_MODE_4) {
                        chip->ecc.bytes = 8;
                        chip->ecc.strength = 4;
                } else {
                        chip->ecc.bytes = 16;
                        chip->ecc.strength = 8;
                }
        } else {
                chip->ecc.mode = NAND_ECC_SOFT;
                chip->ecc.algo = NAND_ECC_HAMMING;
        }

        if (ctrl->version >= FSL_IFC_VERSION_1_1_0)
                fsl_ifc_sram_init(priv);

        /*
         * As IFC version 2.0.0 has 16KB of internal SRAM as compared to older
         * versions which had 8KB. Hence bufnum mask needs to be updated.
         */
        if (ctrl->version >= FSL_IFC_VERSION_2_0_0)
                priv->bufnum_mask = (priv->bufnum_mask * 2) + 1;

        return 0;
}

static int fsl_ifc_chip_remove(struct fsl_ifc_mtd *priv)
{
        struct mtd_info *mtd = nand_to_mtd(&priv->chip);

        nand_release(mtd);

        kfree(mtd->name);

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

        ifc_nand_ctrl->chips[priv->bank] = NULL;

        return 0;
}

static int match_bank(struct fsl_ifc_global __iomem *ifc_global, int bank,
                      phys_addr_t addr)
{
        u32 cspr = ifc_in32(&ifc_global->cspr_cs[bank].cspr);

        if (!(cspr & CSPR_V))
                return 0;
        if ((cspr & CSPR_MSEL) != CSPR_MSEL_NAND)
                return 0;

        return (cspr & CSPR_BA) == convert_ifc_address(addr);
}

static DEFINE_MUTEX(fsl_ifc_nand_mutex);

static int fsl_ifc_nand_probe(struct platform_device *dev)
{
        struct fsl_ifc_runtime __iomem *ifc;
        struct fsl_ifc_mtd *priv;
        struct resource res;
        static const char *part_probe_types[]
                = { "cmdlinepart", "RedBoot", "ofpart", NULL };
        int ret;
        int bank;
        struct device_node *node = dev->dev.of_node;
        struct mtd_info *mtd;

        if (!fsl_ifc_ctrl_dev || !fsl_ifc_ctrl_dev->rregs)
                return -ENODEV;
        ifc = fsl_ifc_ctrl_dev->rregs;

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

        /* find which chip select it is connected to */
        for (bank = 0; bank < fsl_ifc_ctrl_dev->banks; bank++) {
                if (match_bank(fsl_ifc_ctrl_dev->gregs, bank, res.start))
                        break;
        }

        if (bank >= fsl_ifc_ctrl_dev->banks) {
                dev_err(&dev->dev, "%s: address did not match any chip selects\n",
                        __func__);
                return -ENODEV;
        }

        priv = devm_kzalloc(&dev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        mutex_lock(&fsl_ifc_nand_mutex);
        if (!fsl_ifc_ctrl_dev->nand) {
                ifc_nand_ctrl = kzalloc(sizeof(*ifc_nand_ctrl), GFP_KERNEL);
                if (!ifc_nand_ctrl) {
                        mutex_unlock(&fsl_ifc_nand_mutex);
                        return -ENOMEM;
                }

                ifc_nand_ctrl->read_bytes = 0;
                ifc_nand_ctrl->index = 0;
                ifc_nand_ctrl->addr = NULL;
                fsl_ifc_ctrl_dev->nand = ifc_nand_ctrl;

                nand_hw_control_init(&ifc_nand_ctrl->controller);
        } else {
                ifc_nand_ctrl = fsl_ifc_ctrl_dev->nand;
        }
        mutex_unlock(&fsl_ifc_nand_mutex);

        ifc_nand_ctrl->chips[bank] = priv;
        priv->bank = bank;
        priv->ctrl = fsl_ifc_ctrl_dev;
        priv->dev = &dev->dev;

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

        dev_set_drvdata(priv->dev, priv);

        ifc_out32(IFC_NAND_EVTER_EN_OPC_EN |
                  IFC_NAND_EVTER_EN_FTOER_EN |
                  IFC_NAND_EVTER_EN_WPER_EN,
                  &ifc->ifc_nand.nand_evter_en);

        /* enable NAND Machine Interrupts */
        ifc_out32(IFC_NAND_EVTER_INTR_OPCIR_EN |
                  IFC_NAND_EVTER_INTR_FTOERIR_EN |
                  IFC_NAND_EVTER_INTR_WPERIR_EN,
                  &ifc->ifc_nand.nand_evter_intr_en);

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

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

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

        ret = fsl_ifc_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);

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

err:
        fsl_ifc_chip_remove(priv);
        return ret;
}

static int fsl_ifc_nand_remove(struct platform_device *dev)
{
        struct fsl_ifc_mtd *priv = dev_get_drvdata(&dev->dev);

        fsl_ifc_chip_remove(priv);

        mutex_lock(&fsl_ifc_nand_mutex);
        ifc_nand_ctrl->counter--;
        if (!ifc_nand_ctrl->counter) {
                fsl_ifc_ctrl_dev->nand = NULL;
                kfree(ifc_nand_ctrl);
        }
        mutex_unlock(&fsl_ifc_nand_mutex);

        return 0;
}

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

static struct platform_driver fsl_ifc_nand_driver = {
        .driver = {
                .name   = "fsl,ifc-nand",
                .of_match_table = fsl_ifc_nand_match,
        },
        .probe       = fsl_ifc_nand_probe,
        .remove      = fsl_ifc_nand_remove,
};

module_platform_driver(fsl_ifc_nand_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Freescale");
MODULE_DESCRIPTION("Freescale Integrated Flash Controller MTD NAND driver");