/*
 * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
 * Copyright 2008 Sascha Hauer, kernel@pengutronix.de
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 */

#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/of_device.h>

#include <asm/mach/flash.h>
#include <linux/platform_data/mtd-mxc_nand.h>

#define DRIVER_NAME "mxc_nand"

/* Addresses for NFC registers */
#define NFC_V1_V2_BUF_SIZE              (host->regs + 0x00)
#define NFC_V1_V2_BUF_ADDR              (host->regs + 0x04)
#define NFC_V1_V2_FLASH_ADDR            (host->regs + 0x06)
#define NFC_V1_V2_FLASH_CMD             (host->regs + 0x08)
#define NFC_V1_V2_CONFIG                (host->regs + 0x0a)
#define NFC_V1_V2_ECC_STATUS_RESULT     (host->regs + 0x0c)
#define NFC_V1_V2_RSLTMAIN_AREA         (host->regs + 0x0e)
#define NFC_V1_V2_RSLTSPARE_AREA        (host->regs + 0x10)
#define NFC_V1_V2_WRPROT                (host->regs + 0x12)
#define NFC_V1_UNLOCKSTART_BLKADDR      (host->regs + 0x14)
#define NFC_V1_UNLOCKEND_BLKADDR        (host->regs + 0x16)
#define NFC_V21_UNLOCKSTART_BLKADDR0    (host->regs + 0x20)
#define NFC_V21_UNLOCKSTART_BLKADDR1    (host->regs + 0x24)
#define NFC_V21_UNLOCKSTART_BLKADDR2    (host->regs + 0x28)
#define NFC_V21_UNLOCKSTART_BLKADDR3    (host->regs + 0x2c)
#define NFC_V21_UNLOCKEND_BLKADDR0      (host->regs + 0x22)
#define NFC_V21_UNLOCKEND_BLKADDR1      (host->regs + 0x26)
#define NFC_V21_UNLOCKEND_BLKADDR2      (host->regs + 0x2a)
#define NFC_V21_UNLOCKEND_BLKADDR3      (host->regs + 0x2e)
#define NFC_V1_V2_NF_WRPRST             (host->regs + 0x18)
#define NFC_V1_V2_CONFIG1               (host->regs + 0x1a)
#define NFC_V1_V2_CONFIG2               (host->regs + 0x1c)

#define NFC_V2_CONFIG1_ECC_MODE_4       (1 << 0)
#define NFC_V1_V2_CONFIG1_SP_EN         (1 << 2)
#define NFC_V1_V2_CONFIG1_ECC_EN        (1 << 3)
#define NFC_V1_V2_CONFIG1_INT_MSK       (1 << 4)
#define NFC_V1_V2_CONFIG1_BIG           (1 << 5)
#define NFC_V1_V2_CONFIG1_RST           (1 << 6)
#define NFC_V1_V2_CONFIG1_CE            (1 << 7)
#define NFC_V2_CONFIG1_ONE_CYCLE        (1 << 8)
#define NFC_V2_CONFIG1_PPB(x)           (((x) & 0x3) << 9)
#define NFC_V2_CONFIG1_FP_INT           (1 << 11)

#define NFC_V1_V2_CONFIG2_INT           (1 << 15)

/*
 * Operation modes for the NFC. Valid for v1, v2 and v3
 * type controllers.
 */
#define NFC_CMD                         (1 << 0)
#define NFC_ADDR                        (1 << 1)
#define NFC_INPUT                       (1 << 2)
#define NFC_OUTPUT                      (1 << 3)
#define NFC_ID                          (1 << 4)
#define NFC_STATUS                      (1 << 5)

#define NFC_V3_FLASH_CMD                (host->regs_axi + 0x00)
#define NFC_V3_FLASH_ADDR0              (host->regs_axi + 0x04)

#define NFC_V3_CONFIG1                  (host->regs_axi + 0x34)
#define NFC_V3_CONFIG1_SP_EN            (1 << 0)
#define NFC_V3_CONFIG1_RBA(x)           (((x) & 0x7 ) << 4)

#define NFC_V3_ECC_STATUS_RESULT        (host->regs_axi + 0x38)

#define NFC_V3_LAUNCH                   (host->regs_axi + 0x40)

#define NFC_V3_WRPROT                   (host->regs_ip + 0x0)
#define NFC_V3_WRPROT_LOCK_TIGHT        (1 << 0)
#define NFC_V3_WRPROT_LOCK              (1 << 1)
#define NFC_V3_WRPROT_UNLOCK            (1 << 2)
#define NFC_V3_WRPROT_BLS_UNLOCK        (2 << 6)

#define NFC_V3_WRPROT_UNLOCK_BLK_ADD0   (host->regs_ip + 0x04)

#define NFC_V3_CONFIG2                  (host->regs_ip + 0x24)
#define NFC_V3_CONFIG2_PS_512                   (0 << 0)
#define NFC_V3_CONFIG2_PS_2048                  (1 << 0)
#define NFC_V3_CONFIG2_PS_4096                  (2 << 0)
#define NFC_V3_CONFIG2_ONE_CYCLE                (1 << 2)
#define NFC_V3_CONFIG2_ECC_EN                   (1 << 3)
#define NFC_V3_CONFIG2_2CMD_PHASES              (1 << 4)
#define NFC_V3_CONFIG2_NUM_ADDR_PHASE0          (1 << 5)
#define NFC_V3_CONFIG2_ECC_MODE_8               (1 << 6)
#define NFC_V3_CONFIG2_PPB(x, shift)            (((x) & 0x3) << shift)
#define NFC_V3_CONFIG2_NUM_ADDR_PHASE1(x)       (((x) & 0x3) << 12)
#define NFC_V3_CONFIG2_INT_MSK                  (1 << 15)
#define NFC_V3_CONFIG2_ST_CMD(x)                (((x) & 0xff) << 24)
#define NFC_V3_CONFIG2_SPAS(x)                  (((x) & 0xff) << 16)

#define NFC_V3_CONFIG3                          (host->regs_ip + 0x28)
#define NFC_V3_CONFIG3_ADD_OP(x)                (((x) & 0x3) << 0)
#define NFC_V3_CONFIG3_FW8                      (1 << 3)
#define NFC_V3_CONFIG3_SBB(x)                   (((x) & 0x7) << 8)
#define NFC_V3_CONFIG3_NUM_OF_DEVICES(x)        (((x) & 0x7) << 12)
#define NFC_V3_CONFIG3_RBB_MODE                 (1 << 15)
#define NFC_V3_CONFIG3_NO_SDMA                  (1 << 20)

#define NFC_V3_IPC                      (host->regs_ip + 0x2C)
#define NFC_V3_IPC_CREQ                 (1 << 0)
#define NFC_V3_IPC_INT                  (1 << 31)

#define NFC_V3_DELAY_LINE               (host->regs_ip + 0x34)

struct mxc_nand_host;

struct mxc_nand_devtype_data {
        void (*preset)(struct mtd_info *);
        int (*read_page)(struct nand_chip *chip, void *buf, void *oob, bool ecc,
                         int page);
        void (*send_cmd)(struct mxc_nand_host *, uint16_t, int);
        void (*send_addr)(struct mxc_nand_host *, uint16_t, int);
        void (*send_page)(struct mtd_info *, unsigned int);
        void (*send_read_id)(struct mxc_nand_host *);
        uint16_t (*get_dev_status)(struct mxc_nand_host *);
        int (*check_int)(struct mxc_nand_host *);
        void (*irq_control)(struct mxc_nand_host *, int);
        u32 (*get_ecc_status)(struct mxc_nand_host *);
        const struct mtd_ooblayout_ops *ooblayout;
        void (*select_chip)(struct mtd_info *mtd, int chip);
        int (*setup_data_interface)(struct mtd_info *mtd, int csline,
                                    const struct nand_data_interface *conf);
        void (*enable_hwecc)(struct nand_chip *chip, bool enable);

        /*
         * On i.MX21 the CONFIG2:INT bit cannot be read if interrupts are masked
         * (CONFIG1:INT_MSK is set). To handle this the driver uses
         * enable_irq/disable_irq_nosync instead of CONFIG1:INT_MSK
         */
        int irqpending_quirk;
        int needs_ip;

        size_t regs_offset;
        size_t spare0_offset;
        size_t axi_offset;

        int spare_len;
        int eccbytes;
        int eccsize;
        int ppb_shift;
};

struct mxc_nand_host {
        struct nand_chip        nand;
        struct device           *dev;

        void __iomem            *spare0;
        void __iomem            *main_area0;

        void __iomem            *base;
        void __iomem            *regs;
        void __iomem            *regs_axi;
        void __iomem            *regs_ip;
        int                     status_request;
        struct clk              *clk;
        int                     clk_act;
        int                     irq;
        int                     eccsize;
        int                     used_oobsize;
        int                     active_cs;

        struct completion       op_completion;

        uint8_t                 *data_buf;
        unsigned int            buf_start;

        const struct mxc_nand_devtype_data *devtype_data;
        struct mxc_nand_platform_data pdata;
};

static const char * const part_probes[] = {
        "cmdlinepart", "RedBoot", "ofpart", NULL };

static void memcpy32_fromio(void *trg, const void __iomem  *src, size_t size)
{
        int i;
        u32 *t = trg;
        const __iomem u32 *s = src;

        for (i = 0; i < (size >> 2); i++)
                *t++ = __raw_readl(s++);
}

static void memcpy16_fromio(void *trg, const void __iomem  *src, size_t size)
{
        int i;
        u16 *t = trg;
        const __iomem u16 *s = src;

        /* We assume that src (IO) is always 32bit aligned */
        if (PTR_ALIGN(trg, 4) == trg && IS_ALIGNED(size, 4)) {
                memcpy32_fromio(trg, src, size);
                return;
        }

        for (i = 0; i < (size >> 1); i++)
                *t++ = __raw_readw(s++);
}

static inline void memcpy32_toio(void __iomem *trg, const void *src, int size)
{
        /* __iowrite32_copy use 32bit size values so divide by 4 */
        __iowrite32_copy(trg, src, size / 4);
}

static void memcpy16_toio(void __iomem *trg, const void *src, int size)
{
        int i;
        __iomem u16 *t = trg;
        const u16 *s = src;

        /* We assume that trg (IO) is always 32bit aligned */
        if (PTR_ALIGN(src, 4) == src && IS_ALIGNED(size, 4)) {
                memcpy32_toio(trg, src, size);
                return;
        }

        for (i = 0; i < (size >> 1); i++)
                __raw_writew(*s++, t++);
}

/*
 * The controller splits a page into data chunks of 512 bytes + partial oob.
 * There are writesize / 512 such chunks, the size of the partial oob parts is
 * oobsize / #chunks rounded down to a multiple of 2. The last oob chunk then
 * contains additionally the byte lost by rounding (if any).
 * This function handles the needed shuffling between host->data_buf (which
 * holds a page in natural order, i.e. writesize bytes data + oobsize bytes
 * spare) and the NFC buffer.
 */
static void copy_spare(struct mtd_info *mtd, bool bfrom, void *buf)
{
        struct nand_chip *this = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(this);
        u16 i, oob_chunk_size;
        u16 num_chunks = mtd->writesize / 512;

        u8 *d = buf;
        u8 __iomem *s = host->spare0;
        u16 sparebuf_size = host->devtype_data->spare_len;

        /* size of oob chunk for all but possibly the last one */
        oob_chunk_size = (host->used_oobsize / num_chunks) & ~1;

        if (bfrom) {
                for (i = 0; i < num_chunks - 1; i++)
                        memcpy16_fromio(d + i * oob_chunk_size,
                                        s + i * sparebuf_size,
                                        oob_chunk_size);

                /* the last chunk */
                memcpy16_fromio(d + i * oob_chunk_size,
                                s + i * sparebuf_size,
                                host->used_oobsize - i * oob_chunk_size);
        } else {
                for (i = 0; i < num_chunks - 1; i++)
                        memcpy16_toio(&s[i * sparebuf_size],
                                      &d[i * oob_chunk_size],
                                      oob_chunk_size);

                /* the last chunk */
                memcpy16_toio(&s[i * sparebuf_size],
                              &d[i * oob_chunk_size],
                              host->used_oobsize - i * oob_chunk_size);
        }
}

/*
 * MXC NANDFC can only perform full page+spare or spare-only read/write.  When
 * the upper layers perform a read/write buf operation, the saved column address
 * is used to index into the full page. So usually this function is called with
 * column == 0 (unless no column cycle is needed indicated by column == -1)
 */
static void mxc_do_addr_cycle(struct mtd_info *mtd, int column, int page_addr)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);

        /* Write out column address, if necessary */
        if (column != -1) {
                host->devtype_data->send_addr(host, column & 0xff,
                                              page_addr == -1);
                if (mtd->writesize > 512)
                        /* another col addr cycle for 2k page */
                        host->devtype_data->send_addr(host,
                                                      (column >> 8) & 0xff,
                                                      false);
        }

        /* Write out page address, if necessary */
        if (page_addr != -1) {
                /* paddr_0 - p_addr_7 */
                host->devtype_data->send_addr(host, (page_addr & 0xff), false);

                if (mtd->writesize > 512) {
                        if (mtd->size >= 0x10000000) {
                                /* paddr_8 - paddr_15 */
                                host->devtype_data->send_addr(host,
                                                (page_addr >> 8) & 0xff,
                                                false);
                                host->devtype_data->send_addr(host,
                                                (page_addr >> 16) & 0xff,
                                                true);
                        } else
                                /* paddr_8 - paddr_15 */
                                host->devtype_data->send_addr(host,
                                                (page_addr >> 8) & 0xff, true);
                } else {
                        if (nand_chip->options & NAND_ROW_ADDR_3) {
                                /* paddr_8 - paddr_15 */
                                host->devtype_data->send_addr(host,
                                                (page_addr >> 8) & 0xff,
                                                false);
                                host->devtype_data->send_addr(host,
                                                (page_addr >> 16) & 0xff,
                                                true);
                        } else
                                /* paddr_8 - paddr_15 */
                                host->devtype_data->send_addr(host,
                                                (page_addr >> 8) & 0xff, true);
                }
        }
}

static int check_int_v3(struct mxc_nand_host *host)
{
        uint32_t tmp;

        tmp = readl(NFC_V3_IPC);
        if (!(tmp & NFC_V3_IPC_INT))
                return 0;

        tmp &= ~NFC_V3_IPC_INT;
        writel(tmp, NFC_V3_IPC);

        return 1;
}

static int check_int_v1_v2(struct mxc_nand_host *host)
{
        uint32_t tmp;

        tmp = readw(NFC_V1_V2_CONFIG2);
        if (!(tmp & NFC_V1_V2_CONFIG2_INT))
                return 0;

        if (!host->devtype_data->irqpending_quirk)
                writew(tmp & ~NFC_V1_V2_CONFIG2_INT, NFC_V1_V2_CONFIG2);

        return 1;
}

static void irq_control_v1_v2(struct mxc_nand_host *host, int activate)
{
        uint16_t tmp;

        tmp = readw(NFC_V1_V2_CONFIG1);

        if (activate)
                tmp &= ~NFC_V1_V2_CONFIG1_INT_MSK;
        else
                tmp |= NFC_V1_V2_CONFIG1_INT_MSK;

        writew(tmp, NFC_V1_V2_CONFIG1);
}

static void irq_control_v3(struct mxc_nand_host *host, int activate)
{
        uint32_t tmp;

        tmp = readl(NFC_V3_CONFIG2);

        if (activate)
                tmp &= ~NFC_V3_CONFIG2_INT_MSK;
        else
                tmp |= NFC_V3_CONFIG2_INT_MSK;

        writel(tmp, NFC_V3_CONFIG2);
}

static void irq_control(struct mxc_nand_host *host, int activate)
{
        if (host->devtype_data->irqpending_quirk) {
                if (activate)
                        enable_irq(host->irq);
                else
                        disable_irq_nosync(host->irq);
        } else {
                host->devtype_data->irq_control(host, activate);
        }
}

static u32 get_ecc_status_v1(struct mxc_nand_host *host)
{
        return readw(NFC_V1_V2_ECC_STATUS_RESULT);
}

static u32 get_ecc_status_v2(struct mxc_nand_host *host)
{
        return readl(NFC_V1_V2_ECC_STATUS_RESULT);
}

static u32 get_ecc_status_v3(struct mxc_nand_host *host)
{
        return readl(NFC_V3_ECC_STATUS_RESULT);
}

static irqreturn_t mxc_nfc_irq(int irq, void *dev_id)
{
        struct mxc_nand_host *host = dev_id;

        if (!host->devtype_data->check_int(host))
                return IRQ_NONE;

        irq_control(host, 0);

        complete(&host->op_completion);

        return IRQ_HANDLED;
}

/* This function polls the NANDFC to wait for the basic operation to
 * complete by checking the INT bit of config2 register.
 */
static int wait_op_done(struct mxc_nand_host *host, int useirq)
{
        int ret = 0;

        /*
         * If operation is already complete, don't bother to setup an irq or a
         * loop.
         */
        if (host->devtype_data->check_int(host))
                return 0;

        if (useirq) {
                unsigned long timeout;

                reinit_completion(&host->op_completion);

                irq_control(host, 1);

                timeout = wait_for_completion_timeout(&host->op_completion, HZ);
                if (!timeout && !host->devtype_data->check_int(host)) {
                        dev_dbg(host->dev, "timeout waiting for irq\n");
                        ret = -ETIMEDOUT;
                }
        } else {
                int max_retries = 8000;
                int done;

                do {
                        udelay(1);

                        done = host->devtype_data->check_int(host);
                        if (done)
                                break;

                } while (--max_retries);

                if (!done) {
                        dev_dbg(host->dev, "timeout polling for completion\n");
                        ret = -ETIMEDOUT;
                }
        }

        WARN_ONCE(ret < 0, "timeout! useirq=%d\n", useirq);

        return ret;
}

static void send_cmd_v3(struct mxc_nand_host *host, uint16_t cmd, int useirq)
{
        /* fill command */
        writel(cmd, NFC_V3_FLASH_CMD);

        /* send out command */
        writel(NFC_CMD, NFC_V3_LAUNCH);

        /* Wait for operation to complete */
        wait_op_done(host, useirq);
}

/* This function issues the specified command to the NAND device and
 * waits for completion. */
static void send_cmd_v1_v2(struct mxc_nand_host *host, uint16_t cmd, int useirq)
{
        dev_dbg(host->dev, "send_cmd(host, 0x%x, %d)\n", cmd, useirq);

        writew(cmd, NFC_V1_V2_FLASH_CMD);
        writew(NFC_CMD, NFC_V1_V2_CONFIG2);

        if (host->devtype_data->irqpending_quirk && (cmd == NAND_CMD_RESET)) {
                int max_retries = 100;
                /* Reset completion is indicated by NFC_CONFIG2 */
                /* being set to 0 */
                while (max_retries-- > 0) {
                        if (readw(NFC_V1_V2_CONFIG2) == 0) {
                                break;
                        }
                        udelay(1);
                }
                if (max_retries < 0)
                        dev_dbg(host->dev, "%s: RESET failed\n", __func__);
        } else {
                /* Wait for operation to complete */
                wait_op_done(host, useirq);
        }
}

static void send_addr_v3(struct mxc_nand_host *host, uint16_t addr, int islast)
{
        /* fill address */
        writel(addr, NFC_V3_FLASH_ADDR0);

        /* send out address */
        writel(NFC_ADDR, NFC_V3_LAUNCH);

        wait_op_done(host, 0);
}

/* This function sends an address (or partial address) to the
 * NAND device. The address is used to select the source/destination for
 * a NAND command. */
static void send_addr_v1_v2(struct mxc_nand_host *host, uint16_t addr, int islast)
{
        dev_dbg(host->dev, "send_addr(host, 0x%x %d)\n", addr, islast);

        writew(addr, NFC_V1_V2_FLASH_ADDR);
        writew(NFC_ADDR, NFC_V1_V2_CONFIG2);

        /* Wait for operation to complete */
        wait_op_done(host, islast);
}

static void send_page_v3(struct mtd_info *mtd, unsigned int ops)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        uint32_t tmp;

        tmp = readl(NFC_V3_CONFIG1);
        tmp &= ~(7 << 4);
        writel(tmp, NFC_V3_CONFIG1);

        /* transfer data from NFC ram to nand */
        writel(ops, NFC_V3_LAUNCH);

        wait_op_done(host, false);
}

static void send_page_v2(struct mtd_info *mtd, unsigned int ops)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);

        /* NANDFC buffer 0 is used for page read/write */
        writew(host->active_cs << 4, NFC_V1_V2_BUF_ADDR);

        writew(ops, NFC_V1_V2_CONFIG2);

        /* Wait for operation to complete */
        wait_op_done(host, true);
}

static void send_page_v1(struct mtd_info *mtd, unsigned int ops)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        int bufs, i;

        if (mtd->writesize > 512)
                bufs = 4;
        else
                bufs = 1;

        for (i = 0; i < bufs; i++) {

                /* NANDFC buffer 0 is used for page read/write */
                writew((host->active_cs << 4) | i, NFC_V1_V2_BUF_ADDR);

                writew(ops, NFC_V1_V2_CONFIG2);

                /* Wait for operation to complete */
                wait_op_done(host, true);
        }
}

static void send_read_id_v3(struct mxc_nand_host *host)
{
        /* Read ID into main buffer */
        writel(NFC_ID, NFC_V3_LAUNCH);

        wait_op_done(host, true);

        memcpy32_fromio(host->data_buf, host->main_area0, 16);
}

/* Request the NANDFC to perform a read of the NAND device ID. */
static void send_read_id_v1_v2(struct mxc_nand_host *host)
{
        /* NANDFC buffer 0 is used for device ID output */
        writew(host->active_cs << 4, NFC_V1_V2_BUF_ADDR);

        writew(NFC_ID, NFC_V1_V2_CONFIG2);

        /* Wait for operation to complete */
        wait_op_done(host, true);

        memcpy32_fromio(host->data_buf, host->main_area0, 16);
}

static uint16_t get_dev_status_v3(struct mxc_nand_host *host)
{
        writew(NFC_STATUS, NFC_V3_LAUNCH);
        wait_op_done(host, true);

        return readl(NFC_V3_CONFIG1) >> 16;
}

/* This function requests the NANDFC to perform a read of the
 * NAND device status and returns the current status. */
static uint16_t get_dev_status_v1_v2(struct mxc_nand_host *host)
{
        void __iomem *main_buf = host->main_area0;
        uint32_t store;
        uint16_t ret;

        writew(host->active_cs << 4, NFC_V1_V2_BUF_ADDR);

        /*
         * The device status is stored in main_area0. To
         * prevent corruption of the buffer save the value
         * and restore it afterwards.
         */
        store = readl(main_buf);

        writew(NFC_STATUS, NFC_V1_V2_CONFIG2);
        wait_op_done(host, true);

        ret = readw(main_buf);

        writel(store, main_buf);

        return ret;
}

static void mxc_nand_enable_hwecc_v1_v2(struct nand_chip *chip, bool enable)
{
        struct mxc_nand_host *host = nand_get_controller_data(chip);
        uint16_t config1;

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

        config1 = readw(NFC_V1_V2_CONFIG1);

        if (enable)
                config1 |= NFC_V1_V2_CONFIG1_ECC_EN;
        else
                config1 &= ~NFC_V1_V2_CONFIG1_ECC_EN;

        writew(config1, NFC_V1_V2_CONFIG1);
}

static void mxc_nand_enable_hwecc_v3(struct nand_chip *chip, bool enable)
{
        struct mxc_nand_host *host = nand_get_controller_data(chip);
        uint32_t config2;

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

        config2 = readl(NFC_V3_CONFIG2);

        if (enable)
                config2 |= NFC_V3_CONFIG2_ECC_EN;
        else
                config2 &= ~NFC_V3_CONFIG2_ECC_EN;

        writel(config2, NFC_V3_CONFIG2);
}

/* This functions is used by upper layer to checks if device is ready */
static int mxc_nand_dev_ready(struct mtd_info *mtd)
{
        /*
         * NFC handles R/B internally. Therefore, this function
         * always returns status as ready.
         */
        return 1;
}

static int mxc_nand_read_page_v1(struct nand_chip *chip, void *buf, void *oob,
                                 bool ecc, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct mxc_nand_host *host = nand_get_controller_data(chip);
        unsigned int bitflips_corrected = 0;
        int no_subpages;
        int i;

        host->devtype_data->enable_hwecc(chip, ecc);

        host->devtype_data->send_cmd(host, NAND_CMD_READ0, false);
        mxc_do_addr_cycle(mtd, 0, page);

        if (mtd->writesize > 512)
                host->devtype_data->send_cmd(host, NAND_CMD_READSTART, true);

        no_subpages = mtd->writesize >> 9;

        for (i = 0; i < no_subpages; i++) {
                uint16_t ecc_stats;

                /* NANDFC buffer 0 is used for page read/write */
                writew((host->active_cs << 4) | i, NFC_V1_V2_BUF_ADDR);

                writew(NFC_OUTPUT, NFC_V1_V2_CONFIG2);

                /* Wait for operation to complete */
                wait_op_done(host, true);

                ecc_stats = get_ecc_status_v1(host);

                ecc_stats >>= 2;

                if (buf && ecc) {
                        switch (ecc_stats & 0x3) {
                        case 0:
                        default:
                                break;
                        case 1:
                                mtd->ecc_stats.corrected++;
                                bitflips_corrected = 1;
                                break;
                        case 2:
                                mtd->ecc_stats.failed++;
                                break;
                        }
                }
        }

        if (buf)
                memcpy32_fromio(buf, host->main_area0, mtd->writesize);
        if (oob)
                copy_spare(mtd, true, oob);

        return bitflips_corrected;
}

static int mxc_nand_read_page_v2_v3(struct nand_chip *chip, void *buf,
                                    void *oob, bool ecc, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct mxc_nand_host *host = nand_get_controller_data(chip);
        unsigned int max_bitflips = 0;
        u32 ecc_stat, err;
        int no_subpages;
        u8 ecc_bit_mask, err_limit;

        host->devtype_data->enable_hwecc(chip, ecc);

        host->devtype_data->send_cmd(host, NAND_CMD_READ0, false);
        mxc_do_addr_cycle(mtd, 0, page);

        if (mtd->writesize > 512)
                host->devtype_data->send_cmd(host,
                                NAND_CMD_READSTART, true);

        host->devtype_data->send_page(mtd, NFC_OUTPUT);

        if (buf)
                memcpy32_fromio(buf, host->main_area0, mtd->writesize);
        if (oob)
                copy_spare(mtd, true, oob);

        ecc_bit_mask = (host->eccsize == 4) ? 0x7 : 0xf;
        err_limit = (host->eccsize == 4) ? 0x4 : 0x8;

        no_subpages = mtd->writesize >> 9;

        ecc_stat = host->devtype_data->get_ecc_status(host);

        do {
                err = ecc_stat & ecc_bit_mask;
                if (err > err_limit) {
                        mtd->ecc_stats.failed++;
                } else {
                        mtd->ecc_stats.corrected += err;
                        max_bitflips = max_t(unsigned int, max_bitflips, err);
                }

                ecc_stat >>= 4;
        } while (--no_subpages);

        return max_bitflips;
}

static int mxc_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip,
                              uint8_t *buf, int oob_required, int page)
{
        struct mxc_nand_host *host = nand_get_controller_data(chip);
        void *oob_buf;

        if (oob_required)
                oob_buf = chip->oob_poi;
        else
                oob_buf = NULL;

        return host->devtype_data->read_page(chip, buf, oob_buf, 1, page);
}

static int mxc_nand_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
                                  uint8_t *buf, int oob_required, int page)
{
        struct mxc_nand_host *host = nand_get_controller_data(chip);
        void *oob_buf;

        if (oob_required)
                oob_buf = chip->oob_poi;
        else
                oob_buf = NULL;

        return host->devtype_data->read_page(chip, buf, oob_buf, 0, page);
}

static int mxc_nand_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
                             int page)
{
        struct mxc_nand_host *host = nand_get_controller_data(chip);

        return host->devtype_data->read_page(chip, NULL, chip->oob_poi, 0,
                                             page);
}

static int mxc_nand_write_page(struct nand_chip *chip, const uint8_t *buf,
                               bool ecc, int page)
{
        struct mtd_info *mtd = nand_to_mtd(chip);
        struct mxc_nand_host *host = nand_get_controller_data(chip);

        host->devtype_data->enable_hwecc(chip, ecc);

        host->devtype_data->send_cmd(host, NAND_CMD_SEQIN, false);
        mxc_do_addr_cycle(mtd, 0, page);

        memcpy32_toio(host->main_area0, buf, mtd->writesize);
        copy_spare(mtd, false, chip->oob_poi);

        host->devtype_data->send_page(mtd, NFC_INPUT);
        host->devtype_data->send_cmd(host, NAND_CMD_PAGEPROG, true);
        mxc_do_addr_cycle(mtd, 0, page);

        return 0;
}

static int mxc_nand_write_page_ecc(struct mtd_info *mtd, struct nand_chip *chip,
                                   const uint8_t *buf, int oob_required,
                                   int page)
{
        return mxc_nand_write_page(chip, buf, true, page);
}

static int mxc_nand_write_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
                                   const uint8_t *buf, int oob_required, int page)
{
        return mxc_nand_write_page(chip, buf, false, page);
}

static int mxc_nand_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
                              int page)
{
        struct mxc_nand_host *host = nand_get_controller_data(chip);

        memset(host->data_buf, 0xff, mtd->writesize);

        return mxc_nand_write_page(chip, host->data_buf, false, page);
}

static u_char mxc_nand_read_byte(struct mtd_info *mtd)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        uint8_t ret;

        /* Check for status request */
        if (host->status_request)
                return host->devtype_data->get_dev_status(host) & 0xFF;

        if (nand_chip->options & NAND_BUSWIDTH_16) {
                /* only take the lower byte of each word */
                ret = *(uint16_t *)(host->data_buf + host->buf_start);

                host->buf_start += 2;
        } else {
                ret = *(uint8_t *)(host->data_buf + host->buf_start);
                host->buf_start++;
        }

        dev_dbg(host->dev, "%s: ret=0x%hhx (start=%u)\n", __func__, ret, host->buf_start);
        return ret;
}

static uint16_t mxc_nand_read_word(struct mtd_info *mtd)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        uint16_t ret;

        ret = *(uint16_t *)(host->data_buf + host->buf_start);
        host->buf_start += 2;

        return ret;
}

/* Write data of length len to buffer buf. The data to be
 * written on NAND Flash is first copied to RAMbuffer. After the Data Input
 * Operation by the NFC, the data is written to NAND Flash */
static void mxc_nand_write_buf(struct mtd_info *mtd,
                                const u_char *buf, int len)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        u16 col = host->buf_start;
        int n = mtd->oobsize + mtd->writesize - col;

        n = min(n, len);

        memcpy(host->data_buf + col, buf, n);

        host->buf_start += n;
}

/* Read the data buffer from the NAND Flash. To read the data from NAND
 * Flash first the data output cycle is initiated by the NFC, which copies
 * the data to RAMbuffer. This data of length len is then copied to buffer buf.
 */
static void mxc_nand_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        u16 col = host->buf_start;
        int n = mtd->oobsize + mtd->writesize - col;

        n = min(n, len);

        memcpy(buf, host->data_buf + col, n);

        host->buf_start += n;
}

/* This function is used by upper layer for select and
 * deselect of the NAND chip */
static void mxc_nand_select_chip_v1_v3(struct mtd_info *mtd, int chip)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);

        if (chip == -1) {
                /* Disable the NFC clock */
                if (host->clk_act) {
                        clk_disable_unprepare(host->clk);
                        host->clk_act = 0;
                }
                return;

        }

        if (!host->clk_act) {
                /* Enable the NFC clock */
                clk_prepare_enable(host->clk);
                host->clk_act = 1;
        }
}

static void mxc_nand_select_chip_v2(struct mtd_info *mtd, int chip)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);

        if (chip == -1) {
                /* Disable the NFC clock */
                if (host->clk_act) {
                        clk_disable_unprepare(host->clk);
                        host->clk_act = 0;
                }
                return;
        }

        if (!host->clk_act) {
                /* Enable the NFC clock */
                clk_prepare_enable(host->clk);
                host->clk_act = 1;
        }

        host->active_cs = chip;
        writew(host->active_cs << 4, NFC_V1_V2_BUF_ADDR);
}

#define MXC_V1_ECCBYTES         5

static int mxc_v1_ooblayout_ecc(struct mtd_info *mtd, int section,
                                struct mtd_oob_region *oobregion)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);

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

        oobregion->offset = (section * 16) + 6;
        oobregion->length = MXC_V1_ECCBYTES;

        return 0;
}

static int mxc_v1_ooblayout_free(struct mtd_info *mtd, int section,
                                 struct mtd_oob_region *oobregion)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);

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

        if (!section) {
                if (mtd->writesize <= 512) {
                        oobregion->offset = 0;
                        oobregion->length = 5;
                } else {
                        oobregion->offset = 2;
                        oobregion->length = 4;
                }
        } else {
                oobregion->offset = ((section - 1) * 16) + MXC_V1_ECCBYTES + 6;
                if (section < nand_chip->ecc.steps)
                        oobregion->length = (section * 16) + 6 -
                                            oobregion->offset;
                else
                        oobregion->length = mtd->oobsize - oobregion->offset;
        }

        return 0;
}

static const struct mtd_ooblayout_ops mxc_v1_ooblayout_ops = {
        .ecc = mxc_v1_ooblayout_ecc,
        .free = mxc_v1_ooblayout_free,
};

static int mxc_v2_ooblayout_ecc(struct mtd_info *mtd, int section,
                                struct mtd_oob_region *oobregion)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        int stepsize = nand_chip->ecc.bytes == 9 ? 16 : 26;

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

        oobregion->offset = (section * stepsize) + 7;
        oobregion->length = nand_chip->ecc.bytes;

        return 0;
}

static int mxc_v2_ooblayout_free(struct mtd_info *mtd, int section,
                                 struct mtd_oob_region *oobregion)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        int stepsize = nand_chip->ecc.bytes == 9 ? 16 : 26;

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

        if (!section) {
                if (mtd->writesize <= 512) {
                        oobregion->offset = 0;
                        oobregion->length = 5;
                } else {
                        oobregion->offset = 2;
                        oobregion->length = 4;
                }
        } else {
                oobregion->offset = section * stepsize;
                oobregion->length = 7;
        }

        return 0;
}

static const struct mtd_ooblayout_ops mxc_v2_ooblayout_ops = {
        .ecc = mxc_v2_ooblayout_ecc,
        .free = mxc_v2_ooblayout_free,
};

/*
 * v2 and v3 type controllers can do 4bit or 8bit ecc depending
 * on how much oob the nand chip has. For 8bit ecc we need at least
 * 26 bytes of oob data per 512 byte block.
 */
static int get_eccsize(struct mtd_info *mtd)
{
        int oobbytes_per_512 = 0;

        oobbytes_per_512 = mtd->oobsize * 512 / mtd->writesize;

        if (oobbytes_per_512 < 26)
                return 4;
        else
                return 8;
}

static void preset_v1(struct mtd_info *mtd)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        uint16_t config1 = 0;

        if (nand_chip->ecc.mode == NAND_ECC_HW && mtd->writesize)
                config1 |= NFC_V1_V2_CONFIG1_ECC_EN;

        if (!host->devtype_data->irqpending_quirk)
                config1 |= NFC_V1_V2_CONFIG1_INT_MSK;

        host->eccsize = 1;

        writew(config1, NFC_V1_V2_CONFIG1);
        /* preset operation */

        /* Unlock the internal RAM Buffer */
        writew(0x2, NFC_V1_V2_CONFIG);

        /* Blocks to be unlocked */
        writew(0x0, NFC_V1_UNLOCKSTART_BLKADDR);
        writew(0xffff, NFC_V1_UNLOCKEND_BLKADDR);

        /* Unlock Block Command for given address range */
        writew(0x4, NFC_V1_V2_WRPROT);
}

static int mxc_nand_v2_setup_data_interface(struct mtd_info *mtd, int csline,
                                        const struct nand_data_interface *conf)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        int tRC_min_ns, tRC_ps, ret;
        unsigned long rate, rate_round;
        const struct nand_sdr_timings *timings;
        u16 config1;

        timings = nand_get_sdr_timings(conf);
        if (IS_ERR(timings))
                return -ENOTSUPP;

        config1 = readw(NFC_V1_V2_CONFIG1);

        tRC_min_ns = timings->tRC_min / 1000;
        rate = 1000000000 / tRC_min_ns;

        /*
         * For tRC < 30ns we have to use EDO mode. In this case the controller
         * does one access per clock cycle. Otherwise the controller does one
         * access in two clock cycles, thus we have to double the rate to the
         * controller.
         */
        if (tRC_min_ns < 30) {
                rate_round = clk_round_rate(host->clk, rate);
                config1 |= NFC_V2_CONFIG1_ONE_CYCLE;
                tRC_ps = 1000000000 / (rate_round / 1000);
        } else {
                rate *= 2;
                rate_round = clk_round_rate(host->clk, rate);
                config1 &= ~NFC_V2_CONFIG1_ONE_CYCLE;
                tRC_ps = 1000000000 / (rate_round / 1000 / 2);
        }

        /*
         * The timing values compared against are from the i.MX25 Automotive
         * datasheet, Table 50. NFC Timing Parameters
         */
        if (timings->tCLS_min > tRC_ps - 1000 ||
            timings->tCLH_min > tRC_ps - 2000 ||
            timings->tCS_min > tRC_ps - 1000 ||
            timings->tCH_min > tRC_ps - 2000 ||
            timings->tWP_min > tRC_ps - 1500 ||
            timings->tALS_min > tRC_ps ||
            timings->tALH_min > tRC_ps - 3000 ||
            timings->tDS_min > tRC_ps ||
            timings->tDH_min > tRC_ps - 5000 ||
            timings->tWC_min > 2 * tRC_ps ||
            timings->tWH_min > tRC_ps - 2500 ||
            timings->tRR_min > 6 * tRC_ps ||
            timings->tRP_min > 3 * tRC_ps / 2 ||
            timings->tRC_min > 2 * tRC_ps ||
            timings->tREH_min > (tRC_ps / 2) - 2500) {
                dev_dbg(host->dev, "Timing out of bounds\n");
                return -EINVAL;
        }

        if (csline == NAND_DATA_IFACE_CHECK_ONLY)
                return 0;

        ret = clk_set_rate(host->clk, rate);
        if (ret)
                return ret;

        writew(config1, NFC_V1_V2_CONFIG1);

        dev_dbg(host->dev, "Setting rate to %ldHz, %s mode\n", rate_round,
                config1 & NFC_V2_CONFIG1_ONE_CYCLE ? "One cycle (EDO)" :
                "normal");

        return 0;
}

static void preset_v2(struct mtd_info *mtd)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        uint16_t config1 = 0;

        config1 |= NFC_V2_CONFIG1_FP_INT;

        if (!host->devtype_data->irqpending_quirk)
                config1 |= NFC_V1_V2_CONFIG1_INT_MSK;

        if (mtd->writesize) {
                uint16_t pages_per_block = mtd->erasesize / mtd->writesize;

                if (nand_chip->ecc.mode == NAND_ECC_HW)
                        config1 |= NFC_V1_V2_CONFIG1_ECC_EN;

                host->eccsize = get_eccsize(mtd);
                if (host->eccsize == 4)
                        config1 |= NFC_V2_CONFIG1_ECC_MODE_4;

                config1 |= NFC_V2_CONFIG1_PPB(ffs(pages_per_block) - 6);
        } else {
                host->eccsize = 1;
        }

        writew(config1, NFC_V1_V2_CONFIG1);
        /* preset operation */

        /* Unlock the internal RAM Buffer */
        writew(0x2, NFC_V1_V2_CONFIG);

        /* Blocks to be unlocked */
        writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR0);
        writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR1);
        writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR2);
        writew(0x0, NFC_V21_UNLOCKSTART_BLKADDR3);
        writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR0);
        writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR1);
        writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR2);
        writew(0xffff, NFC_V21_UNLOCKEND_BLKADDR3);

        /* Unlock Block Command for given address range */
        writew(0x4, NFC_V1_V2_WRPROT);
}

static void preset_v3(struct mtd_info *mtd)
{
        struct nand_chip *chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(chip);
        uint32_t config2, config3;
        int i, addr_phases;

        writel(NFC_V3_CONFIG1_RBA(0), NFC_V3_CONFIG1);
        writel(NFC_V3_IPC_CREQ, NFC_V3_IPC);

        /* Unlock the internal RAM Buffer */
        writel(NFC_V3_WRPROT_BLS_UNLOCK | NFC_V3_WRPROT_UNLOCK,
                        NFC_V3_WRPROT);

        /* Blocks to be unlocked */
        for (i = 0; i < NAND_MAX_CHIPS; i++)
                writel(0xffff << 16, NFC_V3_WRPROT_UNLOCK_BLK_ADD0 + (i << 2));

        writel(0, NFC_V3_IPC);

        config2 = NFC_V3_CONFIG2_ONE_CYCLE |
                NFC_V3_CONFIG2_2CMD_PHASES |
                NFC_V3_CONFIG2_SPAS(mtd->oobsize >> 1) |
                NFC_V3_CONFIG2_ST_CMD(0x70) |
                NFC_V3_CONFIG2_INT_MSK |
                NFC_V3_CONFIG2_NUM_ADDR_PHASE0;

        addr_phases = fls(chip->pagemask) >> 3;

        if (mtd->writesize == 2048) {
                config2 |= NFC_V3_CONFIG2_PS_2048;
                config2 |= NFC_V3_CONFIG2_NUM_ADDR_PHASE1(addr_phases);
        } else if (mtd->writesize == 4096) {
                config2 |= NFC_V3_CONFIG2_PS_4096;
                config2 |= NFC_V3_CONFIG2_NUM_ADDR_PHASE1(addr_phases);
        } else {
                config2 |= NFC_V3_CONFIG2_PS_512;
                config2 |= NFC_V3_CONFIG2_NUM_ADDR_PHASE1(addr_phases - 1);
        }

        if (mtd->writesize) {
                if (chip->ecc.mode == NAND_ECC_HW)
                        config2 |= NFC_V3_CONFIG2_ECC_EN;

                config2 |= NFC_V3_CONFIG2_PPB(
                                ffs(mtd->erasesize / mtd->writesize) - 6,
                                host->devtype_data->ppb_shift);
                host->eccsize = get_eccsize(mtd);
                if (host->eccsize == 8)
                        config2 |= NFC_V3_CONFIG2_ECC_MODE_8;
        }

        writel(config2, NFC_V3_CONFIG2);

        config3 = NFC_V3_CONFIG3_NUM_OF_DEVICES(0) |
                        NFC_V3_CONFIG3_NO_SDMA |
                        NFC_V3_CONFIG3_RBB_MODE |
                        NFC_V3_CONFIG3_SBB(6) | /* Reset default */
                        NFC_V3_CONFIG3_ADD_OP(0);

        if (!(chip->options & NAND_BUSWIDTH_16))
                config3 |= NFC_V3_CONFIG3_FW8;

        writel(config3, NFC_V3_CONFIG3);

        writel(0, NFC_V3_DELAY_LINE);
}

/* Used by the upper layer to write command to NAND Flash for
 * different operations to be carried out on NAND Flash */
static void mxc_nand_command(struct mtd_info *mtd, unsigned command,
                                int column, int page_addr)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);

        dev_dbg(host->dev, "mxc_nand_command (cmd = 0x%x, col = 0x%x, page = 0x%x)\n",
              command, column, page_addr);

        /* Reset command state information */
        host->status_request = false;

        /* Command pre-processing step */
        switch (command) {
        case NAND_CMD_RESET:
                host->devtype_data->preset(mtd);
                host->devtype_data->send_cmd(host, command, false);
                break;

        case NAND_CMD_STATUS:
                host->buf_start = 0;
                host->status_request = true;

                host->devtype_data->send_cmd(host, command, true);
                WARN_ONCE(column != -1 || page_addr != -1,
                          "Unexpected column/row value (cmd=%u, col=%d, row=%d)\n",
                          command, column, page_addr);
                mxc_do_addr_cycle(mtd, column, page_addr);
                break;

        case NAND_CMD_READID:
                host->devtype_data->send_cmd(host, command, true);
                mxc_do_addr_cycle(mtd, column, page_addr);
                host->devtype_data->send_read_id(host);
                host->buf_start = 0;
                break;

        case NAND_CMD_ERASE1:
        case NAND_CMD_ERASE2:
                host->devtype_data->send_cmd(host, command, false);
                WARN_ONCE(column != -1,
                          "Unexpected column value (cmd=%u, col=%d)\n",
                          command, column);
                mxc_do_addr_cycle(mtd, column, page_addr);

                break;
        case NAND_CMD_PARAM:
                host->devtype_data->send_cmd(host, command, false);
                mxc_do_addr_cycle(mtd, column, page_addr);
                host->devtype_data->send_page(mtd, NFC_OUTPUT);
                memcpy32_fromio(host->data_buf, host->main_area0, 512);
                host->buf_start = 0;
                break;
        default:
                WARN_ONCE(1, "Unimplemented command (cmd=%u)\n",
                          command);
                break;
        }
}

static int mxc_nand_set_features(struct mtd_info *mtd, struct nand_chip *chip,
                                 int addr, u8 *subfeature_param)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        int i;

        host->buf_start = 0;

        for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
                chip->write_byte(mtd, subfeature_param[i]);

        memcpy32_toio(host->main_area0, host->data_buf, mtd->writesize);
        host->devtype_data->send_cmd(host, NAND_CMD_SET_FEATURES, false);
        mxc_do_addr_cycle(mtd, addr, -1);
        host->devtype_data->send_page(mtd, NFC_INPUT);

        return 0;
}

static int mxc_nand_get_features(struct mtd_info *mtd, struct nand_chip *chip,
                                 int addr, u8 *subfeature_param)
{
        struct nand_chip *nand_chip = mtd_to_nand(mtd);
        struct mxc_nand_host *host = nand_get_controller_data(nand_chip);
        int i;

        host->devtype_data->send_cmd(host, NAND_CMD_GET_FEATURES, false);
        mxc_do_addr_cycle(mtd, addr, -1);
        host->devtype_data->send_page(mtd, NFC_OUTPUT);
        memcpy32_fromio(host->data_buf, host->main_area0, 512);
        host->buf_start = 0;

        for (i = 0; i < ONFI_SUBFEATURE_PARAM_LEN; ++i)
                *subfeature_param++ = chip->read_byte(mtd);

        return 0;
}

/*
 * The generic flash bbt decriptors overlap with our ecc
 * hardware, so define some i.MX specific ones.
 */
static uint8_t bbt_pattern[] = { 'B', 'b', 't', '0' };
static uint8_t 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 | NAND_BBT_PERCHIP,
        .offs = 0,
        .len = 4,
        .veroffs = 4,
        .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 | NAND_BBT_PERCHIP,
        .offs = 0,
        .len = 4,
        .veroffs = 4,
        .maxblocks = 4,
        .pattern = mirror_pattern,
};

/* v1 + irqpending_quirk: i.MX21 */
static const struct mxc_nand_devtype_data imx21_nand_devtype_data = {
        .preset = preset_v1,
        .read_page = mxc_nand_read_page_v1,
        .send_cmd = send_cmd_v1_v2,
        .send_addr = send_addr_v1_v2,
        .send_page = send_page_v1,
        .send_read_id = send_read_id_v1_v2,
        .get_dev_status = get_dev_status_v1_v2,
        .check_int = check_int_v1_v2,
        .irq_control = irq_control_v1_v2,
        .get_ecc_status = get_ecc_status_v1,
        .ooblayout = &mxc_v1_ooblayout_ops,
        .select_chip = mxc_nand_select_chip_v1_v3,
        .enable_hwecc = mxc_nand_enable_hwecc_v1_v2,
        .irqpending_quirk = 1,
        .needs_ip = 0,
        .regs_offset = 0xe00,
        .spare0_offset = 0x800,
        .spare_len = 16,
        .eccbytes = 3,
        .eccsize = 1,
};

/* v1 + !irqpending_quirk: i.MX27, i.MX31 */
static const struct mxc_nand_devtype_data imx27_nand_devtype_data = {
        .preset = preset_v1,
        .read_page = mxc_nand_read_page_v1,
        .send_cmd = send_cmd_v1_v2,
        .send_addr = send_addr_v1_v2,
        .send_page = send_page_v1,
        .send_read_id = send_read_id_v1_v2,
        .get_dev_status = get_dev_status_v1_v2,
        .check_int = check_int_v1_v2,
        .irq_control = irq_control_v1_v2,
        .get_ecc_status = get_ecc_status_v1,
        .ooblayout = &mxc_v1_ooblayout_ops,
        .select_chip = mxc_nand_select_chip_v1_v3,
        .enable_hwecc = mxc_nand_enable_hwecc_v1_v2,
        .irqpending_quirk = 0,
        .needs_ip = 0,
        .regs_offset = 0xe00,
        .spare0_offset = 0x800,
        .axi_offset = 0,
        .spare_len = 16,
        .eccbytes = 3,
        .eccsize = 1,
};

/* v21: i.MX25, i.MX35 */
static const struct mxc_nand_devtype_data imx25_nand_devtype_data = {
        .preset = preset_v2,
        .read_page = mxc_nand_read_page_v2_v3,
        .send_cmd = send_cmd_v1_v2,
        .send_addr = send_addr_v1_v2,
        .send_page = send_page_v2,
        .send_read_id = send_read_id_v1_v2,
        .get_dev_status = get_dev_status_v1_v2,
        .check_int = check_int_v1_v2,
        .irq_control = irq_control_v1_v2,
        .get_ecc_status = get_ecc_status_v2,
        .ooblayout = &mxc_v2_ooblayout_ops,
        .select_chip = mxc_nand_select_chip_v2,
        .setup_data_interface = mxc_nand_v2_setup_data_interface,
        .enable_hwecc = mxc_nand_enable_hwecc_v1_v2,
        .irqpending_quirk = 0,
        .needs_ip = 0,
        .regs_offset = 0x1e00,
        .spare0_offset = 0x1000,
        .axi_offset = 0,
        .spare_len = 64,
        .eccbytes = 9,
        .eccsize = 0,
};

/* v3.2a: i.MX51 */
static const struct mxc_nand_devtype_data imx51_nand_devtype_data = {
        .preset = preset_v3,
        .read_page = mxc_nand_read_page_v2_v3,
        .send_cmd = send_cmd_v3,
        .send_addr = send_addr_v3,
        .send_page = send_page_v3,
        .send_read_id = send_read_id_v3,
        .get_dev_status = get_dev_status_v3,
        .check_int = check_int_v3,
        .irq_control = irq_control_v3,
        .get_ecc_status = get_ecc_status_v3,
        .ooblayout = &mxc_v2_ooblayout_ops,
        .select_chip = mxc_nand_select_chip_v1_v3,
        .enable_hwecc = mxc_nand_enable_hwecc_v3,
        .irqpending_quirk = 0,
        .needs_ip = 1,
        .regs_offset = 0,
        .spare0_offset = 0x1000,
        .axi_offset = 0x1e00,
        .spare_len = 64,
        .eccbytes = 0,
        .eccsize = 0,
        .ppb_shift = 7,
};

/* v3.2b: i.MX53 */
static const struct mxc_nand_devtype_data imx53_nand_devtype_data = {
        .preset = preset_v3,
        .read_page = mxc_nand_read_page_v2_v3,
        .send_cmd = send_cmd_v3,
        .send_addr = send_addr_v3,
        .send_page = send_page_v3,
        .send_read_id = send_read_id_v3,
        .get_dev_status = get_dev_status_v3,
        .check_int = check_int_v3,
        .irq_control = irq_control_v3,
        .get_ecc_status = get_ecc_status_v3,
        .ooblayout = &mxc_v2_ooblayout_ops,
        .select_chip = mxc_nand_select_chip_v1_v3,
        .enable_hwecc = mxc_nand_enable_hwecc_v3,
        .irqpending_quirk = 0,
        .needs_ip = 1,
        .regs_offset = 0,
        .spare0_offset = 0x1000,
        .axi_offset = 0x1e00,
        .spare_len = 64,
        .eccbytes = 0,
        .eccsize = 0,
        .ppb_shift = 8,
};

static inline int is_imx21_nfc(struct mxc_nand_host *host)
{
        return host->devtype_data == &imx21_nand_devtype_data;
}

static inline int is_imx27_nfc(struct mxc_nand_host *host)
{
        return host->devtype_data == &imx27_nand_devtype_data;
}

static inline int is_imx25_nfc(struct mxc_nand_host *host)
{
        return host->devtype_data == &imx25_nand_devtype_data;
}

static inline int is_imx51_nfc(struct mxc_nand_host *host)
{
        return host->devtype_data == &imx51_nand_devtype_data;
}

static inline int is_imx53_nfc(struct mxc_nand_host *host)
{
        return host->devtype_data == &imx53_nand_devtype_data;
}

static const struct platform_device_id mxcnd_devtype[] = {
        {
                .name = "imx21-nand",
                .driver_data = (kernel_ulong_t) &imx21_nand_devtype_data,
        }, {
                .name = "imx27-nand",
                .driver_data = (kernel_ulong_t) &imx27_nand_devtype_data,
        }, {
                .name = "imx25-nand",
                .driver_data = (kernel_ulong_t) &imx25_nand_devtype_data,
        }, {
                .name = "imx51-nand",
                .driver_data = (kernel_ulong_t) &imx51_nand_devtype_data,
        }, {
                .name = "imx53-nand",
                .driver_data = (kernel_ulong_t) &imx53_nand_devtype_data,
        }, {
                /* sentinel */
        }
};
MODULE_DEVICE_TABLE(platform, mxcnd_devtype);

#ifdef CONFIG_OF
static const struct of_device_id mxcnd_dt_ids[] = {
        {
                .compatible = "fsl,imx21-nand",
                .data = &imx21_nand_devtype_data,
        }, {
                .compatible = "fsl,imx27-nand",
                .data = &imx27_nand_devtype_data,
        }, {
                .compatible = "fsl,imx25-nand",
                .data = &imx25_nand_devtype_data,
        }, {
                .compatible = "fsl,imx51-nand",
                .data = &imx51_nand_devtype_data,
        }, {
                .compatible = "fsl,imx53-nand",
                .data = &imx53_nand_devtype_data,
        },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxcnd_dt_ids);

static int __init mxcnd_probe_dt(struct mxc_nand_host *host)
{
        struct device_node *np = host->dev->of_node;
        const struct of_device_id *of_id =
                of_match_device(mxcnd_dt_ids, host->dev);

        if (!np)
                return 1;

        host->devtype_data = of_id->data;

        return 0;
}
#else
static int __init mxcnd_probe_dt(struct mxc_nand_host *host)
{
        return 1;
}
#endif

static int mxcnd_probe(struct platform_device *pdev)
{
        struct nand_chip *this;
        struct mtd_info *mtd;
        struct mxc_nand_host *host;
        struct resource *res;
        int err = 0;

        /* Allocate memory for MTD device structure and private data */
        host = devm_kzalloc(&pdev->dev, sizeof(struct mxc_nand_host),
                        GFP_KERNEL);
        if (!host)
                return -ENOMEM;

        /* allocate a temporary buffer for the nand_scan_ident() */
        host->data_buf = devm_kzalloc(&pdev->dev, PAGE_SIZE, GFP_KERNEL);
        if (!host->data_buf)
                return -ENOMEM;

        host->dev = &pdev->dev;
        /* structures must be linked */
        this = &host->nand;
        mtd = nand_to_mtd(this);
        mtd->dev.parent = &pdev->dev;
        mtd->name = DRIVER_NAME;

        /* 50 us command delay time */
        this->chip_delay = 5;

        nand_set_controller_data(this, host);
        nand_set_flash_node(this, pdev->dev.of_node),
        this->dev_ready = mxc_nand_dev_ready;
        this->cmdfunc = mxc_nand_command;
        this->read_byte = mxc_nand_read_byte;
        this->read_word = mxc_nand_read_word;
        this->write_buf = mxc_nand_write_buf;
        this->read_buf = mxc_nand_read_buf;
        this->set_features = mxc_nand_set_features;
        this->get_features = mxc_nand_get_features;

        host->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(host->clk))
                return PTR_ERR(host->clk);

        err = mxcnd_probe_dt(host);
        if (err > 0) {
                struct mxc_nand_platform_data *pdata =
                                        dev_get_platdata(&pdev->dev);
                if (pdata) {
                        host->pdata = *pdata;
                        host->devtype_data = (struct mxc_nand_devtype_data *)
                                                pdev->id_entry->driver_data;
                } else {
                        err = -ENODEV;
                }
        }
        if (err < 0)
                return err;

        this->setup_data_interface = host->devtype_data->setup_data_interface;

        if (host->devtype_data->needs_ip) {
                res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
                host->regs_ip = devm_ioremap_resource(&pdev->dev, res);
                if (IS_ERR(host->regs_ip))
                        return PTR_ERR(host->regs_ip);

                res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        } else {
                res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        }

        host->base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(host->base))
                return PTR_ERR(host->base);

        host->main_area0 = host->base;

        if (host->devtype_data->regs_offset)
                host->regs = host->base + host->devtype_data->regs_offset;
        host->spare0 = host->base + host->devtype_data->spare0_offset;
        if (host->devtype_data->axi_offset)
                host->regs_axi = host->base + host->devtype_data->axi_offset;

        this->ecc.bytes = host->devtype_data->eccbytes;
        host->eccsize = host->devtype_data->eccsize;

        this->select_chip = host->devtype_data->select_chip;
        this->ecc.size = 512;
        mtd_set_ooblayout(mtd, host->devtype_data->ooblayout);

        if (host->pdata.hw_ecc) {
                this->ecc.mode = NAND_ECC_HW;
        } else {
                this->ecc.mode = NAND_ECC_SOFT;
                this->ecc.algo = NAND_ECC_HAMMING;
        }

        /* NAND bus width determines access functions used by upper layer */
        if (host->pdata.width == 2)
                this->options |= NAND_BUSWIDTH_16;

        /* update flash based bbt */
        if (host->pdata.flash_bbt)
                this->bbt_options |= NAND_BBT_USE_FLASH;

        init_completion(&host->op_completion);

        host->irq = platform_get_irq(pdev, 0);
        if (host->irq < 0)
                return host->irq;

        /*
         * Use host->devtype_data->irq_control() here instead of irq_control()
         * because we must not disable_irq_nosync without having requested the
         * irq.
         */
        host->devtype_data->irq_control(host, 0);

        err = devm_request_irq(&pdev->dev, host->irq, mxc_nfc_irq,
                        0, DRIVER_NAME, host);
        if (err)
                return err;

        err = clk_prepare_enable(host->clk);
        if (err)
                return err;
        host->clk_act = 1;

        /*
         * Now that we "own" the interrupt make sure the interrupt mask bit is
         * cleared on i.MX21. Otherwise we can't read the interrupt status bit
         * on this machine.
         */
        if (host->devtype_data->irqpending_quirk) {
                disable_irq_nosync(host->irq);
                host->devtype_data->irq_control(host, 1);
        }

        /* first scan to find the device and get the page size */
        err = nand_scan_ident(mtd, is_imx25_nfc(host) ? 4 : 1, NULL);
        if (err)
                goto escan;

        switch (this->ecc.mode) {
        case NAND_ECC_HW:
                this->ecc.read_page = mxc_nand_read_page;
                this->ecc.read_page_raw = mxc_nand_read_page_raw;
                this->ecc.read_oob = mxc_nand_read_oob;
                this->ecc.write_page = mxc_nand_write_page_ecc;
                this->ecc.write_page_raw = mxc_nand_write_page_raw;
                this->ecc.write_oob = mxc_nand_write_oob;
                break;

        case NAND_ECC_SOFT:
                break;

        default:
                err = -EINVAL;
                goto escan;
        }

        if (this->bbt_options & NAND_BBT_USE_FLASH) {
                this->bbt_td = &bbt_main_descr;
                this->bbt_md = &bbt_mirror_descr;
        }

        /* allocate the right size buffer now */
        devm_kfree(&pdev->dev, (void *)host->data_buf);
        host->data_buf = devm_kzalloc(&pdev->dev, mtd->writesize + mtd->oobsize,
                                        GFP_KERNEL);
        if (!host->data_buf) {
                err = -ENOMEM;
                goto escan;
        }

        /* Call preset again, with correct writesize this time */
        host->devtype_data->preset(mtd);

        if (!this->ecc.bytes) {
                if (host->eccsize == 8)
                        this->ecc.bytes = 18;
                else if (host->eccsize == 4)
                        this->ecc.bytes = 9;
        }

        /*
         * Experimentation shows that i.MX NFC can only handle up to 218 oob
         * bytes. Limit used_oobsize to 218 so as to not confuse copy_spare()
         * into copying invalid data to/from the spare IO buffer, as this
         * might cause ECC data corruption when doing sub-page write to a
         * partially written page.
         */
        host->used_oobsize = min(mtd->oobsize, 218U);

        if (this->ecc.mode == NAND_ECC_HW) {
                if (is_imx21_nfc(host) || is_imx27_nfc(host))
                        this->ecc.strength = 1;
                else
                        this->ecc.strength = (host->eccsize == 4) ? 4 : 8;
        }

        /* second phase scan */
        err = nand_scan_tail(mtd);
        if (err)
                goto escan;

        /* Register the partitions */
        err = mtd_device_parse_register(mtd, part_probes, NULL,
                                        host->pdata.parts,
                                        host->pdata.nr_parts);
        if (err)
                goto cleanup_nand;

        platform_set_drvdata(pdev, host);

        return 0;

cleanup_nand:
        nand_cleanup(this);
escan:
        if (host->clk_act)
                clk_disable_unprepare(host->clk);

        return err;
}

static int mxcnd_remove(struct platform_device *pdev)
{
        struct mxc_nand_host *host = platform_get_drvdata(pdev);

        nand_release(nand_to_mtd(&host->nand));
        if (host->clk_act)
                clk_disable_unprepare(host->clk);

        return 0;
}

static struct platform_driver mxcnd_driver = {
        .driver = {
                   .name = DRIVER_NAME,
                   .of_match_table = of_match_ptr(mxcnd_dt_ids),
        },
        .id_table = mxcnd_devtype,
        .probe = mxcnd_probe,
        .remove = mxcnd_remove,
};
module_platform_driver(mxcnd_driver);

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("MXC NAND MTD driver");
MODULE_LICENSE("GPL");