drivers/mtd/nand/vf610_nfc.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * 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.
 *
 * 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/rawnand.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);
}