/*
 * Copyright 2009-2015 Freescale Semiconductor, Inc. and others
 *
 * Description: MPC5125, VF610, MCF54418 and Kinetis K70 Nand driver.
 * Ported to U-Boot by Stefan Agner
 * Based on RFC driver posted on Kernel Mailing list by Bill Pringlemeir
 * Jason ported to M54418TWR and MVFA5.
 * Authors: Stefan Agner <stefan.agner@toradex.com>
 *          Bill Pringlemeir <bpringlemeir@nbsps.com>
 *          Shaohui Xie <b21989@freescale.com>
 *          Jason Jin <Jason.jin@freescale.com>
 *
 * Based on original driver mpc5121_nfc.c.
 *
 * SPDX-License-Identifier:     GPL-2.0+
 *
 * Limitations:
 * - Untested on MPC5125 and M54418.
 * - DMA and pipelining not used.
 * - 2K pages or less.
 * - HW ECC: Only 2K page with 64+ OOB.
 * - HW ECC: Only 24 and 32-bit error correction implemented.
 */

#include <common.h>
#include <malloc.h>

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

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

/* Register Offsets */
#define NFC_FLASH_CMD1                  0x3F00
#define NFC_FLASH_CMD2                  0x3F04
#define NFC_COL_ADDR                    0x3F08
#define NFC_ROW_ADDR                    0x3F0c
#define NFC_ROW_ADDR_INC                0x3F14
#define NFC_FLASH_STATUS1               0x3F18
#define NFC_FLASH_STATUS2               0x3F1c
#define NFC_CACHE_SWAP                  0x3F28
#define NFC_SECTOR_SIZE                 0x3F2c
#define NFC_FLASH_CONFIG                0x3F30
#define NFC_IRQ_STATUS                  0x3F38

/* Addresses for NFC MAIN RAM BUFFER areas */
#define NFC_MAIN_AREA(n)                ((n) *  0x1000)

#define PAGE_2K                         0x0800
#define OOB_64                          0x0040
#define OOB_MAX                         0x0100

/*
 * NFC_CMD2[CODE] values. See section:
 *  - 31.4.7 Flash Command Code Description, Vybrid manual
 *  - 23.8.6 Flash Command Sequencer, MPC5125 manual
 *
 * Briefly these are bitmasks of controller cycles.
 */
#define READ_PAGE_CMD_CODE              0x7EE0
#define READ_ONFI_PARAM_CMD_CODE        0x4860
#define PROGRAM_PAGE_CMD_CODE           0x7FC0
#define ERASE_CMD_CODE                  0x4EC0
#define READ_ID_CMD_CODE                0x4804
#define RESET_CMD_CODE                  0x4040
#define STATUS_READ_CMD_CODE            0x4068

/* NFC ECC mode define */
#define ECC_BYPASS                      0
#define ECC_45_BYTE                     6
#define ECC_60_BYTE                     7

/*** Register Mask and bit definitions */

/* NFC_FLASH_CMD1 Field */
#define CMD_BYTE2_MASK                          0xFF000000
#define CMD_BYTE2_SHIFT                         24

/* NFC_FLASH_CM2 Field */
#define CMD_BYTE1_MASK                          0xFF000000
#define CMD_BYTE1_SHIFT                         24
#define CMD_CODE_MASK                           0x00FFFF00
#define CMD_CODE_SHIFT                          8
#define BUFNO_MASK                              0x00000006
#define BUFNO_SHIFT                             1
#define START_BIT                               (1<<0)

/* NFC_COL_ADDR Field */
#define COL_ADDR_MASK                           0x0000FFFF
#define COL_ADDR_SHIFT                          0

/* NFC_ROW_ADDR Field */
#define ROW_ADDR_MASK                           0x00FFFFFF
#define ROW_ADDR_SHIFT                          0
#define ROW_ADDR_CHIP_SEL_RB_MASK               0xF0000000
#define ROW_ADDR_CHIP_SEL_RB_SHIFT              28
#define ROW_ADDR_CHIP_SEL_MASK                  0x0F000000
#define ROW_ADDR_CHIP_SEL_SHIFT                 24

/* NFC_FLASH_STATUS2 Field */
#define STATUS_BYTE1_MASK                       0x000000FF

/* NFC_FLASH_CONFIG Field */
#define CONFIG_ECC_SRAM_ADDR_MASK               0x7FC00000
#define CONFIG_ECC_SRAM_ADDR_SHIFT              22
#define CONFIG_ECC_SRAM_REQ_BIT                 (1<<21)
#define CONFIG_DMA_REQ_BIT                      (1<<20)
#define CONFIG_ECC_MODE_MASK                    0x000E0000
#define CONFIG_ECC_MODE_SHIFT                   17
#define CONFIG_FAST_FLASH_BIT                   (1<<16)
#define CONFIG_16BIT                            (1<<7)
#define CONFIG_BOOT_MODE_BIT                    (1<<6)
#define CONFIG_ADDR_AUTO_INCR_BIT               (1<<5)
#define CONFIG_BUFNO_AUTO_INCR_BIT              (1<<4)
#define CONFIG_PAGE_CNT_MASK                    0xF
#define CONFIG_PAGE_CNT_SHIFT                   0

/* NFC_IRQ_STATUS Field */
#define IDLE_IRQ_BIT                            (1<<29)
#define IDLE_EN_BIT                             (1<<20)
#define CMD_DONE_CLEAR_BIT                      (1<<18)
#define IDLE_CLEAR_BIT                          (1<<17)

#define NFC_TIMEOUT     (1000)

/*
 * ECC status - seems to consume 8 bytes (double word). The documented
 * status byte is located in the lowest byte of the second word (which is
 * the 4th or 7th byte depending on endianness).
 * Calculate an offset to store the ECC status at the end of the buffer.
 */
#define ECC_SRAM_ADDR           (PAGE_2K + OOB_MAX - 8)

#define ECC_STATUS              0x4
#define ECC_STATUS_MASK         0x80
#define ECC_STATUS_ERR_COUNT    0x3F

enum vf610_nfc_alt_buf {
        ALT_BUF_DATA = 0,
        ALT_BUF_ID = 1,
        ALT_BUF_STAT = 2,
        ALT_BUF_ONFI = 3,
};

struct vf610_nfc {
        struct nand_chip chip;
        void __iomem *regs;
        uint buf_offset;
        int write_sz;
        /* Status and ID are in alternate locations. */
        enum vf610_nfc_alt_buf alt_buf;
};

#define mtd_to_nfc(_mtd) nand_get_controller_data(mtd_to_nand(_mtd))

#if defined(CONFIG_SYS_NAND_VF610_NFC_45_ECC_BYTES)
#define ECC_HW_MODE ECC_45_BYTE

static struct nand_ecclayout vf610_nfc_ecc = {
        .eccbytes = 45,
        .eccpos = {19, 20, 21, 22, 23,
                   24, 25, 26, 27, 28, 29, 30, 31,
                   32, 33, 34, 35, 36, 37, 38, 39,
                   40, 41, 42, 43, 44, 45, 46, 47,
                   48, 49, 50, 51, 52, 53, 54, 55,
                   56, 57, 58, 59, 60, 61, 62, 63},
        .oobfree = {
                {.offset = 2,
                 .length = 17} }
};
#elif defined(CONFIG_SYS_NAND_VF610_NFC_60_ECC_BYTES)
#define ECC_HW_MODE ECC_60_BYTE

static struct nand_ecclayout vf610_nfc_ecc = {
        .eccbytes = 60,
        .eccpos = { 4,  5,  6,  7,  8,  9, 10, 11,
                   12, 13, 14, 15, 16, 17, 18, 19,
                   20, 21, 22, 23, 24, 25, 26, 27,
                   28, 29, 30, 31, 32, 33, 34, 35,
                   36, 37, 38, 39, 40, 41, 42, 43,
                   44, 45, 46, 47, 48, 49, 50, 51,
                   52, 53, 54, 55, 56, 57, 58, 59,
                   60, 61, 62, 63 },
        .oobfree = {
                {.offset = 2,
                 .length = 2} }
};
#endif

static inline u32 vf610_nfc_read(struct mtd_info *mtd, uint reg)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);

        return readl(nfc->regs + reg);
}

static inline void vf610_nfc_write(struct mtd_info *mtd, uint reg, u32 val)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);

        writel(val, nfc->regs + reg);
}

static inline void vf610_nfc_set(struct mtd_info *mtd, uint reg, u32 bits)
{
        vf610_nfc_write(mtd, reg, vf610_nfc_read(mtd, reg) | bits);
}

static inline void vf610_nfc_clear(struct mtd_info *mtd, uint reg, u32 bits)
{
        vf610_nfc_write(mtd, reg, vf610_nfc_read(mtd, reg) & ~bits);
}

static inline void vf610_nfc_set_field(struct mtd_info *mtd, u32 reg,
                                       u32 mask, u32 shift, u32 val)
{
        vf610_nfc_write(mtd, reg,
                        (vf610_nfc_read(mtd, reg) & (~mask)) | val << shift);
}

static inline void vf610_nfc_memcpy(void *dst, const void *src, size_t n)
{
        /*
         * Use this accessor for the internal SRAM buffers. On the ARM
         * Freescale Vybrid SoC it's known that the driver can treat
         * the SRAM buffer as if it's memory. Other platform might need
         * to treat the buffers differently.
         *
         * For the time being, use memcpy
         */
        memcpy(dst, src, n);
}

/* Clear flags for upcoming command */
static inline void vf610_nfc_clear_status(void __iomem *regbase)
{
        void __iomem *reg = regbase + NFC_IRQ_STATUS;
        u32 tmp = __raw_readl(reg);
        tmp |= CMD_DONE_CLEAR_BIT | IDLE_CLEAR_BIT;
        __raw_writel(tmp, reg);
}

/* Wait for complete operation */
static void vf610_nfc_done(struct mtd_info *mtd)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        uint start;

        /*
         * Barrier is needed after this write. This write need
         * to be done before reading the next register the first
         * time.
         * vf610_nfc_set implicates such a barrier by using writel
         * to write to the register.
         */
        vf610_nfc_set(mtd, NFC_FLASH_CMD2, START_BIT);

        start = get_timer(0);

        while (!(vf610_nfc_read(mtd, NFC_IRQ_STATUS) & IDLE_IRQ_BIT)) {
                if (get_timer(start) > NFC_TIMEOUT) {
                        printf("Timeout while waiting for IDLE.\n");
                        return;
                }
        }
        vf610_nfc_clear_status(nfc->regs);
}

static u8 vf610_nfc_get_id(struct mtd_info *mtd, int col)
{
        u32 flash_id;

        if (col < 4) {
                flash_id = vf610_nfc_read(mtd, NFC_FLASH_STATUS1);
                flash_id >>= (3 - col) * 8;
        } else {
                flash_id = vf610_nfc_read(mtd, NFC_FLASH_STATUS2);
                flash_id >>= 24;
        }

        return flash_id & 0xff;
}

static u8 vf610_nfc_get_status(struct mtd_info *mtd)
{
        return vf610_nfc_read(mtd, NFC_FLASH_STATUS2) & STATUS_BYTE1_MASK;
}

/* Single command */
static void vf610_nfc_send_command(void __iomem *regbase, u32 cmd_byte1,
                                   u32 cmd_code)
{
        void __iomem *reg = regbase + NFC_FLASH_CMD2;
        u32 tmp;
        vf610_nfc_clear_status(regbase);

        tmp = __raw_readl(reg);
        tmp &= ~(CMD_BYTE1_MASK | CMD_CODE_MASK | BUFNO_MASK);
        tmp |= cmd_byte1 << CMD_BYTE1_SHIFT;
        tmp |= cmd_code << CMD_CODE_SHIFT;
        __raw_writel(tmp, reg);
}

/* Two commands */
static void vf610_nfc_send_commands(void __iomem *regbase, u32 cmd_byte1,
                              u32 cmd_byte2, u32 cmd_code)
{
        void __iomem *reg = regbase + NFC_FLASH_CMD1;
        u32 tmp;
        vf610_nfc_send_command(regbase, cmd_byte1, cmd_code);

        tmp = __raw_readl(reg);
        tmp &= ~CMD_BYTE2_MASK;
        tmp |= cmd_byte2 << CMD_BYTE2_SHIFT;
        __raw_writel(tmp, reg);
}

static void vf610_nfc_addr_cycle(struct mtd_info *mtd, int column, int page)
{
        if (column != -1) {
                struct vf610_nfc *nfc = mtd_to_nfc(mtd);
                if (nfc->chip.options & NAND_BUSWIDTH_16)
                        column = column / 2;
                vf610_nfc_set_field(mtd, NFC_COL_ADDR, COL_ADDR_MASK,
                                    COL_ADDR_SHIFT, column);
        }
        if (page != -1)
                vf610_nfc_set_field(mtd, NFC_ROW_ADDR, ROW_ADDR_MASK,
                                    ROW_ADDR_SHIFT, page);
}

static inline void vf610_nfc_ecc_mode(struct mtd_info *mtd, int ecc_mode)
{
        vf610_nfc_set_field(mtd, NFC_FLASH_CONFIG,
                            CONFIG_ECC_MODE_MASK,
                            CONFIG_ECC_MODE_SHIFT, ecc_mode);
}

static inline void vf610_nfc_transfer_size(void __iomem *regbase, int size)
{
        __raw_writel(size, regbase + NFC_SECTOR_SIZE);
}

/* Send command to NAND chip */
static void vf610_nfc_command(struct mtd_info *mtd, unsigned command,
                              int column, int page)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        int trfr_sz = nfc->chip.options & NAND_BUSWIDTH_16 ? 1 : 0;

        nfc->buf_offset = max(column, 0);
        nfc->alt_buf = ALT_BUF_DATA;

        switch (command) {
        case NAND_CMD_SEQIN:
                /* Use valid column/page from preread... */
                vf610_nfc_addr_cycle(mtd, column, page);
                nfc->buf_offset = 0;

                /*
                 * SEQIN => data => PAGEPROG sequence is done by the controller
                 * hence we do not need to issue the command here...
                 */
                return;
        case NAND_CMD_PAGEPROG:
                trfr_sz += nfc->write_sz;
                vf610_nfc_ecc_mode(mtd, ECC_HW_MODE);
                vf610_nfc_transfer_size(nfc->regs, trfr_sz);
                vf610_nfc_send_commands(nfc->regs, NAND_CMD_SEQIN,
                                        command, PROGRAM_PAGE_CMD_CODE);
                break;

        case NAND_CMD_RESET:
                vf610_nfc_transfer_size(nfc->regs, 0);
                vf610_nfc_send_command(nfc->regs, command, RESET_CMD_CODE);
                break;

        case NAND_CMD_READOOB:
                trfr_sz += mtd->oobsize;
                column = mtd->writesize;
                vf610_nfc_transfer_size(nfc->regs, trfr_sz);
                vf610_nfc_send_commands(nfc->regs, NAND_CMD_READ0,
                                        NAND_CMD_READSTART, READ_PAGE_CMD_CODE);
                vf610_nfc_addr_cycle(mtd, column, page);
                vf610_nfc_ecc_mode(mtd, ECC_BYPASS);
                break;

        case NAND_CMD_READ0:
                trfr_sz += mtd->writesize + mtd->oobsize;
                vf610_nfc_transfer_size(nfc->regs, trfr_sz);
                vf610_nfc_ecc_mode(mtd, ECC_HW_MODE);
                vf610_nfc_send_commands(nfc->regs, NAND_CMD_READ0,
                                        NAND_CMD_READSTART, READ_PAGE_CMD_CODE);
                vf610_nfc_addr_cycle(mtd, column, page);
                break;

        case NAND_CMD_PARAM:
                nfc->alt_buf = ALT_BUF_ONFI;
                trfr_sz = 3 * sizeof(struct nand_onfi_params);
                vf610_nfc_transfer_size(nfc->regs, trfr_sz);
                vf610_nfc_send_command(nfc->regs, NAND_CMD_PARAM,
                                       READ_ONFI_PARAM_CMD_CODE);
                vf610_nfc_set_field(mtd, NFC_ROW_ADDR, ROW_ADDR_MASK,
                                    ROW_ADDR_SHIFT, column);
                vf610_nfc_ecc_mode(mtd, ECC_BYPASS);
                break;

        case NAND_CMD_ERASE1:
                vf610_nfc_transfer_size(nfc->regs, 0);
                vf610_nfc_send_commands(nfc->regs, command,
                                        NAND_CMD_ERASE2, ERASE_CMD_CODE);
                vf610_nfc_addr_cycle(mtd, column, page);
                break;

        case NAND_CMD_READID:
                nfc->alt_buf = ALT_BUF_ID;
                nfc->buf_offset = 0;
                vf610_nfc_transfer_size(nfc->regs, 0);
                vf610_nfc_send_command(nfc->regs, command, READ_ID_CMD_CODE);
                vf610_nfc_set_field(mtd, NFC_ROW_ADDR, ROW_ADDR_MASK,
                                    ROW_ADDR_SHIFT, column);
                break;

        case NAND_CMD_STATUS:
                nfc->alt_buf = ALT_BUF_STAT;
                vf610_nfc_transfer_size(nfc->regs, 0);
                vf610_nfc_send_command(nfc->regs, command, STATUS_READ_CMD_CODE);
                break;
        default:
                return;
        }

        vf610_nfc_done(mtd);

        nfc->write_sz = 0;
}

/* Read data from NFC buffers */
static void vf610_nfc_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        uint c = nfc->buf_offset;

        /* Alternate buffers are only supported through read_byte */
        if (nfc->alt_buf)
                return;

        vf610_nfc_memcpy(buf, nfc->regs + NFC_MAIN_AREA(0) + c, len);

        nfc->buf_offset += len;
}

/* Write data to NFC buffers */
static void vf610_nfc_write_buf(struct mtd_info *mtd, const uint8_t *buf,
                                int len)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        uint c = nfc->buf_offset;
        uint l;

        l = min_t(uint, len, mtd->writesize + mtd->oobsize - c);
        vf610_nfc_memcpy(nfc->regs + NFC_MAIN_AREA(0) + c, buf, l);

        nfc->write_sz += l;
        nfc->buf_offset += l;
}

/* Read byte from NFC buffers */
static uint8_t vf610_nfc_read_byte(struct mtd_info *mtd)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        u8 tmp;
        uint c = nfc->buf_offset;

        switch (nfc->alt_buf) {
        case ALT_BUF_ID:
                tmp = vf610_nfc_get_id(mtd, c);
                break;
        case ALT_BUF_STAT:
                tmp = vf610_nfc_get_status(mtd);
                break;
#ifdef __LITTLE_ENDIAN
        case ALT_BUF_ONFI:
                /* Reverse byte since the controller uses big endianness */
                c = nfc->buf_offset ^ 0x3;
                /* fall-through */
#endif
        default:
                tmp = *((u8 *)(nfc->regs + NFC_MAIN_AREA(0) + c));
                break;
        }
        nfc->buf_offset++;
        return tmp;
}

/* Read word from NFC buffers */
static u16 vf610_nfc_read_word(struct mtd_info *mtd)
{
        u16 tmp;

        vf610_nfc_read_buf(mtd, (u_char *)&tmp, sizeof(tmp));
        return tmp;
}

/* If not provided, upper layers apply a fixed delay. */
static int vf610_nfc_dev_ready(struct mtd_info *mtd)
{
        /* NFC handles R/B internally; always ready.  */
        return 1;
}

/*
 * This function supports Vybrid only (MPC5125 would have full RB and four CS)
 */
static void vf610_nfc_select_chip(struct mtd_info *mtd, int chip)
{
#ifdef CONFIG_VF610
        u32 tmp = vf610_nfc_read(mtd, NFC_ROW_ADDR);
        tmp &= ~(ROW_ADDR_CHIP_SEL_RB_MASK | ROW_ADDR_CHIP_SEL_MASK);

        if (chip >= 0) {
                tmp |= 1 << ROW_ADDR_CHIP_SEL_RB_SHIFT;
                tmp |= (1 << chip) << ROW_ADDR_CHIP_SEL_SHIFT;
        }

        vf610_nfc_write(mtd, NFC_ROW_ADDR, tmp);
#endif
}

/* Count the number of 0's in buff upto max_bits */
static inline int count_written_bits(uint8_t *buff, int size, int max_bits)
{
        uint32_t *buff32 = (uint32_t *)buff;
        int k, written_bits = 0;

        for (k = 0; k < (size / 4); k++) {
                written_bits += hweight32(~buff32[k]);
                if (written_bits > max_bits)
                        break;
        }

        return written_bits;
}

static inline int vf610_nfc_correct_data(struct mtd_info *mtd, uint8_t *dat,
                                         uint8_t *oob, int page)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        u32 ecc_status_off = NFC_MAIN_AREA(0) + ECC_SRAM_ADDR + ECC_STATUS;
        u8 ecc_status;
        u8 ecc_count;
        int flips;
        int flips_threshold = nfc->chip.ecc.strength / 2;

        ecc_status = vf610_nfc_read(mtd, ecc_status_off) & 0xff;
        ecc_count = ecc_status & ECC_STATUS_ERR_COUNT;

        if (!(ecc_status & ECC_STATUS_MASK))
                return ecc_count;

        /* Read OOB without ECC unit enabled */
        vf610_nfc_command(mtd, NAND_CMD_READOOB, 0, page);
        vf610_nfc_read_buf(mtd, oob, mtd->oobsize);

        /*
         * On an erased page, bit count (including OOB) should be zero or
         * at least less then half of the ECC strength.
         */
        flips = count_written_bits(dat, nfc->chip.ecc.size, flips_threshold);
        flips += count_written_bits(oob, mtd->oobsize, flips_threshold);

        if (unlikely(flips > flips_threshold))
                return -EINVAL;

        /* Erased page. */
        memset(dat, 0xff, nfc->chip.ecc.size);
        memset(oob, 0xff, mtd->oobsize);
        return flips;
}

static int vf610_nfc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
                                uint8_t *buf, int oob_required, int page)
{
        int eccsize = chip->ecc.size;
        int stat;

        vf610_nfc_read_buf(mtd, buf, eccsize);
        if (oob_required)
                vf610_nfc_read_buf(mtd, chip->oob_poi, mtd->oobsize);

        stat = vf610_nfc_correct_data(mtd, buf, chip->oob_poi, page);

        if (stat < 0) {
                mtd->ecc_stats.failed++;
                return 0;
        } else {
                mtd->ecc_stats.corrected += stat;
                return stat;
        }
}

/*
 * ECC will be calculated automatically
 */
static int vf610_nfc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
                               const uint8_t *buf, int oob_required, int page)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);

        vf610_nfc_write_buf(mtd, buf, mtd->writesize);
        if (oob_required)
                vf610_nfc_write_buf(mtd, chip->oob_poi, mtd->oobsize);

        /* Always write whole page including OOB due to HW ECC */
        nfc->write_sz = mtd->writesize + mtd->oobsize;

        return 0;
}

struct vf610_nfc_config {
        int hardware_ecc;
        int width;
        int flash_bbt;
};

static int vf610_nfc_nand_init(int devnum, void __iomem *addr)
{
        struct mtd_info *mtd;
        struct nand_chip *chip;
        struct vf610_nfc *nfc;
        int err = 0;
        struct vf610_nfc_config cfg = {
                .hardware_ecc = 1,
#ifdef CONFIG_SYS_NAND_BUSWIDTH_16BIT
                .width = 16,
#else
                .width = 8,
#endif
                .flash_bbt = 1,
        };

        nfc = malloc(sizeof(*nfc));
        if (!nfc) {
                printf(KERN_ERR "%s: Memory exhausted!\n", __func__);
                return -ENOMEM;
        }

        chip = &nfc->chip;
        nfc->regs = addr;

        mtd = nand_to_mtd(chip);
        nand_set_controller_data(chip, nfc);

        if (cfg.width == 16)
                chip->options |= NAND_BUSWIDTH_16;

        chip->dev_ready = vf610_nfc_dev_ready;
        chip->cmdfunc = vf610_nfc_command;
        chip->read_byte = vf610_nfc_read_byte;
        chip->read_word = vf610_nfc_read_word;
        chip->read_buf = vf610_nfc_read_buf;
        chip->write_buf = vf610_nfc_write_buf;
        chip->select_chip = vf610_nfc_select_chip;

        chip->options |= NAND_NO_SUBPAGE_WRITE;

        chip->ecc.size = PAGE_2K;

        /* Set configuration register. */
        vf610_nfc_clear(mtd, NFC_FLASH_CONFIG, CONFIG_16BIT);
        vf610_nfc_clear(mtd, NFC_FLASH_CONFIG, CONFIG_ADDR_AUTO_INCR_BIT);
        vf610_nfc_clear(mtd, NFC_FLASH_CONFIG, CONFIG_BUFNO_AUTO_INCR_BIT);
        vf610_nfc_clear(mtd, NFC_FLASH_CONFIG, CONFIG_BOOT_MODE_BIT);
        vf610_nfc_clear(mtd, NFC_FLASH_CONFIG, CONFIG_DMA_REQ_BIT);
        vf610_nfc_set(mtd, NFC_FLASH_CONFIG, CONFIG_FAST_FLASH_BIT);

        /* Disable virtual pages, only one elementary transfer unit */
        vf610_nfc_set_field(mtd, NFC_FLASH_CONFIG, CONFIG_PAGE_CNT_MASK,
                            CONFIG_PAGE_CNT_SHIFT, 1);

        /* first scan to find the device and get the page size */
        if (nand_scan_ident(mtd, CONFIG_SYS_MAX_NAND_DEVICE, NULL)) {
                err = -ENXIO;
                goto error;
        }

        if (cfg.width == 16)
                vf610_nfc_set(mtd, NFC_FLASH_CONFIG, CONFIG_16BIT);

        /* Bad block options. */
        if (cfg.flash_bbt)
                chip->bbt_options = NAND_BBT_USE_FLASH | NAND_BBT_NO_OOB |
                                    NAND_BBT_CREATE;

        /* Single buffer only, max 256 OOB minus ECC status */
        if (mtd->writesize + mtd->oobsize > PAGE_2K + OOB_MAX - 8) {
                dev_err(nfc->dev, "Unsupported flash page size\n");
                err = -ENXIO;
                goto error;
        }

        if (cfg.hardware_ecc) {
                if (mtd->writesize != PAGE_2K && mtd->oobsize < 64) {
                        dev_err(nfc->dev, "Unsupported flash with hwecc\n");
                        err = -ENXIO;
                        goto error;
                }

                if (chip->ecc.size != mtd->writesize) {
                        dev_err(nfc->dev, "ecc size: %d\n", chip->ecc.size);
                        dev_err(nfc->dev, "Step size needs to be page size\n");
                        err = -ENXIO;
                        goto error;
                }

                /* Current HW ECC layouts only use 64 bytes of OOB */
                if (mtd->oobsize > 64)
                        mtd->oobsize = 64;

                /* propagate ecc.layout to mtd_info */
                mtd->ecclayout = chip->ecc.layout;
                chip->ecc.read_page = vf610_nfc_read_page;
                chip->ecc.write_page = vf610_nfc_write_page;
                chip->ecc.mode = NAND_ECC_HW;

                chip->ecc.size = PAGE_2K;
                chip->ecc.layout = &vf610_nfc_ecc;
#if defined(CONFIG_SYS_NAND_VF610_NFC_45_ECC_BYTES)
                chip->ecc.strength = 24;
                chip->ecc.bytes = 45;
#elif defined(CONFIG_SYS_NAND_VF610_NFC_60_ECC_BYTES)
                chip->ecc.strength = 32;
                chip->ecc.bytes = 60;
#endif

                /* Set ECC_STATUS offset */
                vf610_nfc_set_field(mtd, NFC_FLASH_CONFIG,
                                    CONFIG_ECC_SRAM_ADDR_MASK,
                                    CONFIG_ECC_SRAM_ADDR_SHIFT,
                                    ECC_SRAM_ADDR >> 3);

                /* Enable ECC status in SRAM */
                vf610_nfc_set(mtd, NFC_FLASH_CONFIG, CONFIG_ECC_SRAM_REQ_BIT);
        }

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

        err = nand_register(devnum, mtd);
        if (err)
                return err;

        return 0;

error:
        return err;
}

void board_nand_init(void)
{
        int err = vf610_nfc_nand_init(0, (void __iomem *)CONFIG_SYS_NAND_BASE);
        if (err)
                printf("VF610 NAND init failed (err %d)\n", err);
}