atmel_nand.c

/*
 *  Copyright © 2003 Rick Bronson
 *
 *  Derived from drivers/mtd/nand/autcpu12.c
 *	 Copyright © 2001 Thomas Gleixner (gleixner@autronix.de)
 *
 *  Derived from drivers/mtd/spia.c
 *	 Copyright © 2000 Steven J. Hill (sjhill@cotw.com)
 *
 *
 *  Add Hardware ECC support for AT91SAM9260 / AT91SAM9263
 *     Richard Genoud (richard.genoud@gmail.com), Adeneo Copyright © 2007
 *
 *     Derived from Das U-Boot source code
 *     		(u-boot-1.1.5/board/atmel/at91sam9263ek/nand.c)
 *     © Copyright 2006 ATMEL Rousset, Lacressonniere Nicolas
 *
 *  Add Programmable Multibit ECC support for various AT91 SoC
 *     © Copyright 2012 ATMEL, Hong Xu
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_gpio.h>
#include <linux/of_mtd.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>

#include <linux/dmaengine.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/platform_data/atmel.h>

#include <mach/cpu.h>

static int use_dma = 1;
module_param(use_dma, int, 0);

static int on_flash_bbt = 0;
module_param(on_flash_bbt, int, 0);

/* Register access macros */
#define ecc_readl(add, reg)				\
	__raw_readl(add + ATMEL_ECC_##reg)
#define ecc_writel(add, reg, value)			\
	__raw_writel((value), add + ATMEL_ECC_##reg)

#include "atmel_nand_ecc.h"	/* Hardware ECC registers */

/* oob layout for large page size
 * bad block info is on bytes 0 and 1
 * the bytes have to be consecutives to avoid
 * several NAND_CMD_RNDOUT during read
 */
static struct nand_ecclayout atmel_oobinfo_large = {
	.eccbytes = 4,
	.eccpos = {60, 61, 62, 63},
	.oobfree = {
		{2, 58}
	},
};

/* oob layout for small page size
 * bad block info is on bytes 4 and 5
 * the bytes have to be consecutives to avoid
 * several NAND_CMD_RNDOUT during read
 */
static struct nand_ecclayout atmel_oobinfo_small = {
	.eccbytes = 4,
	.eccpos = {0, 1, 2, 3},
	.oobfree = {
		{6, 10}
	},
};

struct atmel_nand_host {
	struct nand_chip	nand_chip;
	struct mtd_info		mtd;
	void __iomem		*io_base;
	dma_addr_t		io_phys;
	struct atmel_nand_data	board;
	struct device		*dev;
	void __iomem		*ecc;

	struct completion	comp;
	struct dma_chan		*dma_chan;

	bool			has_pmecc;
	u8			pmecc_corr_cap;
	u16			pmecc_sector_size;
	u32			pmecc_lookup_table_offset;

	int			pmecc_bytes_per_sector;
	int			pmecc_sector_number;
	int			pmecc_degree;	/* Degree of remainders */
	int			pmecc_cw_len;	/* Length of codeword */

	void __iomem		*pmerrloc_base;
	void __iomem		*pmecc_rom_base;

	/* lookup table for alpha_to and index_of */
	void __iomem		*pmecc_alpha_to;
	void __iomem		*pmecc_index_of;

	/* data for pmecc computation */
	int16_t			*pmecc_partial_syn;
	int16_t			*pmecc_si;
	int16_t			*pmecc_smu;	/* Sigma table */
	int16_t			*pmecc_lmu;	/* polynomal order */
	int			*pmecc_mu;
	int			*pmecc_dmu;
	int			*pmecc_delta;
};

static struct nand_ecclayout atmel_pmecc_oobinfo;

static int cpu_has_dma(void)
{
	return cpu_is_at91sam9rl() || cpu_is_at91sam9g45();
}

/*
 * Enable NAND.
 */
static void atmel_nand_enable(struct atmel_nand_host *host)
{
	if (gpio_is_valid(host->board.enable_pin))
		gpio_set_value(host->board.enable_pin, 0);
}

/*
 * Disable NAND.
 */
static void atmel_nand_disable(struct atmel_nand_host *host)
{
	if (gpio_is_valid(host->board.enable_pin))
		gpio_set_value(host->board.enable_pin, 1);
}

/*
 * Hardware specific access to control-lines
 */
static void atmel_nand_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;

	if (ctrl & NAND_CTRL_CHANGE) {
		if (ctrl & NAND_NCE)
			atmel_nand_enable(host);
		else
			atmel_nand_disable(host);
	}
	if (cmd == NAND_CMD_NONE)
		return;

	if (ctrl & NAND_CLE)
		writeb(cmd, host->io_base + (1 << host->board.cle));
	else
		writeb(cmd, host->io_base + (1 << host->board.ale));
}

/*
 * Read the Device Ready pin.
 */
static int atmel_nand_device_ready(struct mtd_info *mtd)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;

	return gpio_get_value(host->board.rdy_pin) ^
                !!host->board.rdy_pin_active_low;
}

/*
 * Minimal-overhead PIO for data access.
 */
static void atmel_read_buf8(struct mtd_info *mtd, u8 *buf, int len)
{
	struct nand_chip	*nand_chip = mtd->priv;

	__raw_readsb(nand_chip->IO_ADDR_R, buf, len);
}

static void atmel_read_buf16(struct mtd_info *mtd, u8 *buf, int len)
{
	struct nand_chip	*nand_chip = mtd->priv;

	__raw_readsw(nand_chip->IO_ADDR_R, buf, len / 2);
}

static void atmel_write_buf8(struct mtd_info *mtd, const u8 *buf, int len)
{
	struct nand_chip	*nand_chip = mtd->priv;

	__raw_writesb(nand_chip->IO_ADDR_W, buf, len);
}

static void atmel_write_buf16(struct mtd_info *mtd, const u8 *buf, int len)
{
	struct nand_chip	*nand_chip = mtd->priv;

	__raw_writesw(nand_chip->IO_ADDR_W, buf, len / 2);
}

static void dma_complete_func(void *completion)
{
	complete(completion);
}

static int atmel_nand_dma_op(struct mtd_info *mtd, void *buf, int len,
			       int is_read)
{
	struct dma_device *dma_dev;
	enum dma_ctrl_flags flags;
	dma_addr_t dma_src_addr, dma_dst_addr, phys_addr;
	struct dma_async_tx_descriptor *tx = NULL;
	dma_cookie_t cookie;
	struct nand_chip *chip = mtd->priv;
	struct atmel_nand_host *host = chip->priv;
	void *p = buf;
	int err = -EIO;
	enum dma_data_direction dir = is_read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;

	if (buf >= high_memory)
		goto err_buf;

	dma_dev = host->dma_chan->device;

	flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT | DMA_COMPL_SKIP_SRC_UNMAP |
		DMA_COMPL_SKIP_DEST_UNMAP;

	phys_addr = dma_map_single(dma_dev->dev, p, len, dir);
	if (dma_mapping_error(dma_dev->dev, phys_addr)) {
		dev_err(host->dev, "Failed to dma_map_single\n");
		goto err_buf;
	}

	if (is_read) {
		dma_src_addr = host->io_phys;
		dma_dst_addr = phys_addr;
	} else {
		dma_src_addr = phys_addr;
		dma_dst_addr = host->io_phys;
	}

	tx = dma_dev->device_prep_dma_memcpy(host->dma_chan, dma_dst_addr,
					     dma_src_addr, len, flags);
	if (!tx) {
		dev_err(host->dev, "Failed to prepare DMA memcpy\n");
		goto err_dma;
	}

	init_completion(&host->comp);
	tx->callback = dma_complete_func;
	tx->callback_param = &host->comp;

	cookie = tx->tx_submit(tx);
	if (dma_submit_error(cookie)) {
		dev_err(host->dev, "Failed to do DMA tx_submit\n");
		goto err_dma;
	}

	dma_async_issue_pending(host->dma_chan);
	wait_for_completion(&host->comp);

	err = 0;

err_dma:
	dma_unmap_single(dma_dev->dev, phys_addr, len, dir);
err_buf:
	if (err != 0)
		dev_warn(host->dev, "Fall back to CPU I/O\n");
	return err;
}

static void atmel_read_buf(struct mtd_info *mtd, u8 *buf, int len)
{
	struct nand_chip *chip = mtd->priv;
	struct atmel_nand_host *host = chip->priv;

	if (use_dma && len > mtd->oobsize)
		/* only use DMA for bigger than oob size: better performances */
		if (atmel_nand_dma_op(mtd, buf, len, 1) == 0)
			return;

	if (host->board.bus_width_16)
		atmel_read_buf16(mtd, buf, len);
	else
		atmel_read_buf8(mtd, buf, len);
}

static void atmel_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
{
	struct nand_chip *chip = mtd->priv;
	struct atmel_nand_host *host = chip->priv;

	if (use_dma && len > mtd->oobsize)
		/* only use DMA for bigger than oob size: better performances */
		if (atmel_nand_dma_op(mtd, (void *)buf, len, 0) == 0)
			return;

	if (host->board.bus_width_16)
		atmel_write_buf16(mtd, buf, len);
	else
		atmel_write_buf8(mtd, buf, len);
}

/*
 * Return number of ecc bytes per sector according to sector size and
 * correction capability
 *
 * Following table shows what at91 PMECC supported:
 * Correction Capability	Sector_512_bytes	Sector_1024_bytes
 * =====================	================	=================
 *                2-bits                 4-bytes                  4-bytes
 *                4-bits                 7-bytes                  7-bytes
 *                8-bits                13-bytes                 14-bytes
 *               12-bits                20-bytes                 21-bytes
 *               24-bits                39-bytes                 42-bytes
 */
static int pmecc_get_ecc_bytes(int cap, int sector_size)
{
	int m = 12 + sector_size / 512;
	return (m * cap + 7) / 8;
}

static void pmecc_config_ecc_layout(struct nand_ecclayout *layout,
	int oobsize, int ecc_len)
{
	int i;

	layout->eccbytes = ecc_len;

	/* ECC will occupy the last ecc_len bytes continuously */
	for (i = 0; i < ecc_len; i++)
		layout->eccpos[i] = oobsize - ecc_len + i;

	layout->oobfree[0].offset = 2;
	layout->oobfree[0].length =
		oobsize - ecc_len - layout->oobfree[0].offset;
}

static void __iomem *pmecc_get_alpha_to(struct atmel_nand_host *host)
{
	int table_size;

	table_size = host->pmecc_sector_size == 512 ?
		PMECC_LOOKUP_TABLE_SIZE_512 : PMECC_LOOKUP_TABLE_SIZE_1024;

	return host->pmecc_rom_base + host->pmecc_lookup_table_offset +
			table_size * sizeof(int16_t);
}

static void pmecc_data_free(struct atmel_nand_host *host)
{
	kfree(host->pmecc_partial_syn);
	kfree(host->pmecc_si);
	kfree(host->pmecc_lmu);
	kfree(host->pmecc_smu);
	kfree(host->pmecc_mu);
	kfree(host->pmecc_dmu);
	kfree(host->pmecc_delta);
}

static int pmecc_data_alloc(struct atmel_nand_host *host)
{
	const int cap = host->pmecc_corr_cap;

	host->pmecc_partial_syn = kzalloc((2 * cap + 1) * sizeof(int16_t),
					GFP_KERNEL);
	host->pmecc_si = kzalloc((2 * cap + 1) * sizeof(int16_t), GFP_KERNEL);
	host->pmecc_lmu = kzalloc((cap + 1) * sizeof(int16_t), GFP_KERNEL);
	host->pmecc_smu = kzalloc((cap + 2) * (2 * cap + 1) * sizeof(int16_t),
					GFP_KERNEL);
	host->pmecc_mu = kzalloc((cap + 1) * sizeof(int), GFP_KERNEL);
	host->pmecc_dmu = kzalloc((cap + 1) * sizeof(int), GFP_KERNEL);
	host->pmecc_delta = kzalloc((cap + 1) * sizeof(int), GFP_KERNEL);

	if (host->pmecc_partial_syn &&
			host->pmecc_si &&
			host->pmecc_lmu &&
			host->pmecc_smu &&
			host->pmecc_mu &&
			host->pmecc_dmu &&
			host->pmecc_delta)
		return 0;

	/* error happened */
	pmecc_data_free(host);
	return -ENOMEM;
}

static void pmecc_gen_syndrome(struct mtd_info *mtd, int sector)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;
	int i;
	uint32_t value;

	/* Fill odd syndromes */
	for (i = 0; i < host->pmecc_corr_cap; i++) {
		value = pmecc_readl_rem_relaxed(host->ecc, sector, i / 2);
		if (i & 1)
			value >>= 16;
		value &= 0xffff;
		host->pmecc_partial_syn[(2 * i) + 1] = (int16_t)value;
	}
}

static void pmecc_substitute(struct mtd_info *mtd)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;
	int16_t __iomem *alpha_to = host->pmecc_alpha_to;
	int16_t __iomem *index_of = host->pmecc_index_of;
	int16_t *partial_syn = host->pmecc_partial_syn;
	const int cap = host->pmecc_corr_cap;
	int16_t *si;
	int i, j;

	/* si[] is a table that holds the current syndrome value,
	 * an element of that table belongs to the field
	 */
	si = host->pmecc_si;

	memset(&si[1], 0, sizeof(int16_t) * (2 * cap - 1));

	/* Computation 2t syndromes based on S(x) */
	/* Odd syndromes */
	for (i = 1; i < 2 * cap; i += 2) {
		for (j = 0; j < host->pmecc_degree; j++) {
			if (partial_syn[i] & ((unsigned short)0x1 << j))
				si[i] = readw_relaxed(alpha_to + i * j) ^ si[i];
		}
	}
	/* Even syndrome = (Odd syndrome) ** 2 */
	for (i = 2, j = 1; j <= cap; i = ++j << 1) {
		if (si[j] == 0) {
			si[i] = 0;
		} else {
			int16_t tmp;

			tmp = readw_relaxed(index_of + si[j]);
			tmp = (tmp * 2) % host->pmecc_cw_len;
			si[i] = readw_relaxed(alpha_to + tmp);
		}
	}

	return;
}

static void pmecc_get_sigma(struct mtd_info *mtd)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;

	int16_t *lmu = host->pmecc_lmu;
	int16_t *si = host->pmecc_si;
	int *mu = host->pmecc_mu;
	int *dmu = host->pmecc_dmu;	/* Discrepancy */
	int *delta = host->pmecc_delta; /* Delta order */
	int cw_len = host->pmecc_cw_len;
	const int16_t cap = host->pmecc_corr_cap;
	const int num = 2 * cap + 1;
	int16_t __iomem	*index_of = host->pmecc_index_of;
	int16_t __iomem	*alpha_to = host->pmecc_alpha_to;
	int i, j, k;
	uint32_t dmu_0_count, tmp;
	int16_t *smu = host->pmecc_smu;

	/* index of largest delta */
	int ro;
	int largest;
	int diff;

	dmu_0_count = 0;

	/* First Row */

	/* Mu */
	mu[0] = -1;

	memset(smu, 0, sizeof(int16_t) * num);
	smu[0] = 1;

	/* discrepancy set to 1 */
	dmu[0] = 1;
	/* polynom order set to 0 */
	lmu[0] = 0;
	delta[0] = (mu[0] * 2 - lmu[0]) >> 1;

	/* Second Row */

	/* Mu */
	mu[1] = 0;
	/* Sigma(x) set to 1 */
	memset(&smu[num], 0, sizeof(int16_t) * num);
	smu[num] = 1;

	/* discrepancy set to S1 */
	dmu[1] = si[1];

	/* polynom order set to 0 */
	lmu[1] = 0;

	delta[1] = (mu[1] * 2 - lmu[1]) >> 1;

	/* Init the Sigma(x) last row */
	memset(&smu[(cap + 1) * num], 0, sizeof(int16_t) * num);

	for (i = 1; i <= cap; i++) {
		mu[i + 1] = i << 1;
		/* Begin Computing Sigma (Mu+1) and L(mu) */
		/* check if discrepancy is set to 0 */
		if (dmu[i] == 0) {
			dmu_0_count++;

			tmp = ((cap - (lmu[i] >> 1) - 1) / 2);
			if ((cap - (lmu[i] >> 1) - 1) & 0x1)
				tmp += 2;
			else
				tmp += 1;

			if (dmu_0_count == tmp) {
				for (j = 0; j <= (lmu[i] >> 1) + 1; j++)
					smu[(cap + 1) * num + j] =
							smu[i * num + j];

				lmu[cap + 1] = lmu[i];
				return;
			}

			/* copy polynom */
			for (j = 0; j <= lmu[i] >> 1; j++)
				smu[(i + 1) * num + j] = smu[i * num + j];

			/* copy previous polynom order to the next */
			lmu[i + 1] = lmu[i];
		} else {
			ro = 0;
			largest = -1;
			/* find largest delta with dmu != 0 */
			for (j = 0; j < i; j++) {
				if ((dmu[j]) && (delta[j] > largest)) {
					largest = delta[j];
					ro = j;
				}
			}

			/* compute difference */
			diff = (mu[i] - mu[ro]);

			/* Compute degree of the new smu polynomial */
			if ((lmu[i] >> 1) > ((lmu[ro] >> 1) + diff))
				lmu[i + 1] = lmu[i];
			else
				lmu[i + 1] = ((lmu[ro] >> 1) + diff) * 2;

			/* Init smu[i+1] with 0 */
			for (k = 0; k < num; k++)
				smu[(i + 1) * num + k] = 0;

			/* Compute smu[i+1] */
			for (k = 0; k <= lmu[ro] >> 1; k++) {
				int16_t a, b, c;

				if (!(smu[ro * num + k] && dmu[i]))
					continue;
				a = readw_relaxed(index_of + dmu[i]);
				b = readw_relaxed(index_of + dmu[ro]);
				c = readw_relaxed(index_of + smu[ro * num + k]);
				tmp = a + (cw_len - b) + c;
				a = readw_relaxed(alpha_to + tmp % cw_len);
				smu[(i + 1) * num + (k + diff)] = a;
			}

			for (k = 0; k <= lmu[i] >> 1; k++)
				smu[(i + 1) * num + k] ^= smu[i * num + k];
		}

		/* End Computing Sigma (Mu+1) and L(mu) */
		/* In either case compute delta */
		delta[i + 1] = (mu[i + 1] * 2 - lmu[i + 1]) >> 1;

		/* Do not compute discrepancy for the last iteration */
		if (i >= cap)
			continue;

		for (k = 0; k <= (lmu[i + 1] >> 1); k++) {
			tmp = 2 * (i - 1);
			if (k == 0) {
				dmu[i + 1] = si[tmp + 3];
			} else if (smu[(i + 1) * num + k] && si[tmp + 3 - k]) {
				int16_t a, b, c;
				a = readw_relaxed(index_of +
						smu[(i + 1) * num + k]);
				b = si[2 * (i - 1) + 3 - k];
				c = readw_relaxed(index_of + b);
				tmp = a + c;
				tmp %= cw_len;
				dmu[i + 1] = readw_relaxed(alpha_to + tmp) ^
					dmu[i + 1];
			}
		}
	}

	return;
}

static int pmecc_err_location(struct mtd_info *mtd)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;
	unsigned long end_time;
	const int cap = host->pmecc_corr_cap;
	const int num = 2 * cap + 1;
	int sector_size = host->pmecc_sector_size;
	int err_nbr = 0;	/* number of error */
	int roots_nbr;		/* number of roots */
	int i;
	uint32_t val;
	int16_t *smu = host->pmecc_smu;

	pmerrloc_writel(host->pmerrloc_base, ELDIS, PMERRLOC_DISABLE);

	for (i = 0; i <= host->pmecc_lmu[cap + 1] >> 1; i++) {
		pmerrloc_writel_sigma_relaxed(host->pmerrloc_base, i,
				      smu[(cap + 1) * num + i]);
		err_nbr++;
	}

	val = (err_nbr - 1) << 16;
	if (sector_size == 1024)
		val |= 1;

	pmerrloc_writel(host->pmerrloc_base, ELCFG, val);
	pmerrloc_writel(host->pmerrloc_base, ELEN,
			sector_size * 8 + host->pmecc_degree * cap);

	end_time = jiffies + msecs_to_jiffies(PMECC_MAX_TIMEOUT_MS);
	while (!(pmerrloc_readl_relaxed(host->pmerrloc_base, ELISR)
		 & PMERRLOC_CALC_DONE)) {
		if (unlikely(time_after(jiffies, end_time))) {
			dev_err(host->dev, "PMECC: Timeout to calculate error location.\n");
			return -1;
		}
		cpu_relax();
	}

	roots_nbr = (pmerrloc_readl_relaxed(host->pmerrloc_base, ELISR)
		& PMERRLOC_ERR_NUM_MASK) >> 8;
	/* Number of roots == degree of smu hence <= cap */
	if (roots_nbr == host->pmecc_lmu[cap + 1] >> 1)
		return err_nbr - 1;

	/* Number of roots does not match the degree of smu
	 * unable to correct error */
	return -1;
}

static void pmecc_correct_data(struct mtd_info *mtd, uint8_t *buf, uint8_t *ecc,
		int sector_num, int extra_bytes, int err_nbr)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;
	int i = 0;
	int byte_pos, bit_pos, sector_size, pos;
	uint32_t tmp;
	uint8_t err_byte;

	sector_size = host->pmecc_sector_size;

	while (err_nbr) {
		tmp = pmerrloc_readl_el_relaxed(host->pmerrloc_base, i) - 1;
		byte_pos = tmp / 8;
		bit_pos  = tmp % 8;

		if (byte_pos >= (sector_size + extra_bytes))
			BUG();	/* should never happen */

		if (byte_pos < sector_size) {
			err_byte = *(buf + byte_pos);
			*(buf + byte_pos) ^= (1 << bit_pos);

			pos = sector_num * host->pmecc_sector_size + byte_pos;
			dev_info(host->dev, "Bit flip in data area, byte_pos: %d, bit_pos: %d, 0x%02x -> 0x%02x\n",
				pos, bit_pos, err_byte, *(buf + byte_pos));
		} else {
			/* Bit flip in OOB area */
			tmp = sector_num * host->pmecc_bytes_per_sector
					+ (byte_pos - sector_size);
			err_byte = ecc[tmp];
			ecc[tmp] ^= (1 << bit_pos);

			pos = tmp + nand_chip->ecc.layout->eccpos[0];
			dev_info(host->dev, "Bit flip in OOB, oob_byte_pos: %d, bit_pos: %d, 0x%02x -> 0x%02x\n",
				pos, bit_pos, err_byte, ecc[tmp]);
		}

		i++;
		err_nbr--;
	}

	return;
}

static int pmecc_correction(struct mtd_info *mtd, u32 pmecc_stat, uint8_t *buf,
	u8 *ecc)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;
	int i, err_nbr, eccbytes;
	uint8_t *buf_pos;

	eccbytes = nand_chip->ecc.bytes;
	for (i = 0; i < eccbytes; i++)
		if (ecc[i] != 0xff)
			goto normal_check;
	/* Erased page, return OK */
	return 0;

normal_check:
	for (i = 0; i < host->pmecc_sector_number; i++) {
		err_nbr = 0;
		if (pmecc_stat & 0x1) {
			buf_pos = buf + i * host->pmecc_sector_size;

			pmecc_gen_syndrome(mtd, i);
			pmecc_substitute(mtd);
			pmecc_get_sigma(mtd);

			err_nbr = pmecc_err_location(mtd);
			if (err_nbr == -1) {
				dev_err(host->dev, "PMECC: Too many errors\n");
				mtd->ecc_stats.failed++;
				return -EIO;
			} else {
				pmecc_correct_data(mtd, buf_pos, ecc, i,
					host->pmecc_bytes_per_sector, err_nbr);
				mtd->ecc_stats.corrected += err_nbr;
			}
		}
		pmecc_stat >>= 1;
	}

	return 0;
}

static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
	struct nand_chip *chip, uint8_t *buf, int oob_required, int page)
{
	struct atmel_nand_host *host = chip->priv;
	int eccsize = chip->ecc.size;
	uint8_t *oob = chip->oob_poi;
	uint32_t *eccpos = chip->ecc.layout->eccpos;
	uint32_t stat;
	unsigned long end_time;

	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_RST);
	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
	pmecc_writel(host->ecc, CFG, (pmecc_readl_relaxed(host->ecc, CFG)
		& ~PMECC_CFG_WRITE_OP) | PMECC_CFG_AUTO_ENABLE);

	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_ENABLE);
	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DATA);

	chip->read_buf(mtd, buf, eccsize);
	chip->read_buf(mtd, oob, mtd->oobsize);

	end_time = jiffies + msecs_to_jiffies(PMECC_MAX_TIMEOUT_MS);
	while ((pmecc_readl_relaxed(host->ecc, SR) & PMECC_SR_BUSY)) {
		if (unlikely(time_after(jiffies, end_time))) {
			dev_err(host->dev, "PMECC: Timeout to get error status.\n");
			return -EIO;
		}
		cpu_relax();
	}

	stat = pmecc_readl_relaxed(host->ecc, ISR);
	if (stat != 0)
		if (pmecc_correction(mtd, stat, buf, &oob[eccpos[0]]) != 0)
			return -EIO;

	return 0;
}

static int atmel_nand_pmecc_write_page(struct mtd_info *mtd,
		struct nand_chip *chip, const uint8_t *buf, int oob_required)
{
	struct atmel_nand_host *host = chip->priv;
	uint32_t *eccpos = chip->ecc.layout->eccpos;
	int i, j;
	unsigned long end_time;

	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_RST);
	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);

	pmecc_writel(host->ecc, CFG, (pmecc_readl_relaxed(host->ecc, CFG) |
		PMECC_CFG_WRITE_OP) & ~PMECC_CFG_AUTO_ENABLE);

	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_ENABLE);
	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DATA);

	chip->write_buf(mtd, (u8 *)buf, mtd->writesize);

	end_time = jiffies + msecs_to_jiffies(PMECC_MAX_TIMEOUT_MS);
	while ((pmecc_readl_relaxed(host->ecc, SR) & PMECC_SR_BUSY)) {
		if (unlikely(time_after(jiffies, end_time))) {
			dev_err(host->dev, "PMECC: Timeout to get ECC value.\n");
			return -EIO;
		}
		cpu_relax();
	}

	for (i = 0; i < host->pmecc_sector_number; i++) {
		for (j = 0; j < host->pmecc_bytes_per_sector; j++) {
			int pos;

			pos = i * host->pmecc_bytes_per_sector + j;
			chip->oob_poi[eccpos[pos]] =
				pmecc_readb_ecc_relaxed(host->ecc, i, j);
		}
	}
	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);

	return 0;
}

static void atmel_pmecc_core_init(struct mtd_info *mtd)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;
	uint32_t val = 0;
	struct nand_ecclayout *ecc_layout;

	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_RST);
	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);

	switch (host->pmecc_corr_cap) {
	case 2:
		val = PMECC_CFG_BCH_ERR2;
		break;
	case 4:
		val = PMECC_CFG_BCH_ERR4;
		break;
	case 8:
		val = PMECC_CFG_BCH_ERR8;
		break;
	case 12:
		val = PMECC_CFG_BCH_ERR12;
		break;
	case 24:
		val = PMECC_CFG_BCH_ERR24;
		break;
	}

	if (host->pmecc_sector_size == 512)
		val |= PMECC_CFG_SECTOR512;
	else if (host->pmecc_sector_size == 1024)
		val |= PMECC_CFG_SECTOR1024;

	switch (host->pmecc_sector_number) {
	case 1:
		val |= PMECC_CFG_PAGE_1SECTOR;
		break;
	case 2:
		val |= PMECC_CFG_PAGE_2SECTORS;
		break;
	case 4:
		val |= PMECC_CFG_PAGE_4SECTORS;
		break;
	case 8:
		val |= PMECC_CFG_PAGE_8SECTORS;
		break;
	}

	val |= (PMECC_CFG_READ_OP | PMECC_CFG_SPARE_DISABLE
		| PMECC_CFG_AUTO_DISABLE);
	pmecc_writel(host->ecc, CFG, val);

	ecc_layout = nand_chip->ecc.layout;
	pmecc_writel(host->ecc, SAREA, mtd->oobsize - 1);
	pmecc_writel(host->ecc, SADDR, ecc_layout->eccpos[0]);
	pmecc_writel(host->ecc, EADDR,
			ecc_layout->eccpos[ecc_layout->eccbytes - 1]);
	/* See datasheet about PMECC Clock Control Register */
	pmecc_writel(host->ecc, CLK, 2);
	pmecc_writel(host->ecc, IDR, 0xff);
	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_ENABLE);
}

static int __init atmel_pmecc_nand_init_params(struct platform_device *pdev,
					 struct atmel_nand_host *host)
{
	struct mtd_info *mtd = &host->mtd;
	struct nand_chip *nand_chip = &host->nand_chip;
	struct resource *regs, *regs_pmerr, *regs_rom;
	int cap, sector_size, err_no;

	cap = host->pmecc_corr_cap;
	sector_size = host->pmecc_sector_size;
	dev_info(host->dev, "Initialize PMECC params, cap: %d, sector: %d\n",
		 cap, sector_size);

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	if (!regs) {
		dev_warn(host->dev,
			"Can't get I/O resource regs for PMECC controller, rolling back on software ECC\n");
		nand_chip->ecc.mode = NAND_ECC_SOFT;
		return 0;
	}

	host->ecc = ioremap(regs->start, resource_size(regs));
	if (host->ecc == NULL) {
		dev_err(host->dev, "ioremap failed\n");
		err_no = -EIO;
		goto err_pmecc_ioremap;
	}

	regs_pmerr = platform_get_resource(pdev, IORESOURCE_MEM, 2);
	regs_rom = platform_get_resource(pdev, IORESOURCE_MEM, 3);
	if (regs_pmerr && regs_rom) {
		host->pmerrloc_base = ioremap(regs_pmerr->start,
			resource_size(regs_pmerr));
		host->pmecc_rom_base = ioremap(regs_rom->start,
			resource_size(regs_rom));
	}

	if (!host->pmerrloc_base || !host->pmecc_rom_base) {
		dev_err(host->dev,
			"Can not get I/O resource for PMECC ERRLOC controller or ROM!\n");
		err_no = -EIO;
		goto err_pmloc_ioremap;
	}

	/* ECC is calculated for the whole page (1 step) */
	nand_chip->ecc.size = mtd->writesize;

	/* set ECC page size and oob layout */
	switch (mtd->writesize) {
	case 2048:
		host->pmecc_degree = PMECC_GF_DIMENSION_13;
		host->pmecc_cw_len = (1 << host->pmecc_degree) - 1;
		host->pmecc_sector_number = mtd->writesize / sector_size;
		host->pmecc_bytes_per_sector = pmecc_get_ecc_bytes(
			cap, sector_size);
		host->pmecc_alpha_to = pmecc_get_alpha_to(host);
		host->pmecc_index_of = host->pmecc_rom_base +
			host->pmecc_lookup_table_offset;

		nand_chip->ecc.steps = 1;
		nand_chip->ecc.strength = cap;
		nand_chip->ecc.bytes = host->pmecc_bytes_per_sector *
				       host->pmecc_sector_number;
		if (nand_chip->ecc.bytes > mtd->oobsize - 2) {
			dev_err(host->dev, "No room for ECC bytes\n");
			err_no = -EINVAL;
			goto err_no_ecc_room;
		}
		pmecc_config_ecc_layout(&atmel_pmecc_oobinfo,
					mtd->oobsize,
					nand_chip->ecc.bytes);
		nand_chip->ecc.layout = &atmel_pmecc_oobinfo;
		break;
	case 512:
	case 1024:
	case 4096:
		/* TODO */
		dev_warn(host->dev,
			"Unsupported page size for PMECC, use Software ECC\n");
	default:
		/* page size not handled by HW ECC */
		/* switching back to soft ECC */
		nand_chip->ecc.mode = NAND_ECC_SOFT;
		return 0;
	}

	/* Allocate data for PMECC computation */
	err_no = pmecc_data_alloc(host);
	if (err_no) {
		dev_err(host->dev,
				"Cannot allocate memory for PMECC computation!\n");
		goto err_pmecc_data_alloc;
	}

	nand_chip->ecc.read_page = atmel_nand_pmecc_read_page;
	nand_chip->ecc.write_page = atmel_nand_pmecc_write_page;

	atmel_pmecc_core_init(mtd);

	return 0;

err_pmecc_data_alloc:
err_no_ecc_room:
err_pmloc_ioremap:
	iounmap(host->ecc);
	if (host->pmerrloc_base)
		iounmap(host->pmerrloc_base);
	if (host->pmecc_rom_base)
		iounmap(host->pmecc_rom_base);
err_pmecc_ioremap:
	return err_no;
}

/*
 * Calculate HW ECC
 *
 * function called after a write
 *
 * mtd:        MTD block structure
 * dat:        raw data (unused)
 * ecc_code:   buffer for ECC
 */
static int atmel_nand_calculate(struct mtd_info *mtd,
		const u_char *dat, unsigned char *ecc_code)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;
	unsigned int ecc_value;

	/* get the first 2 ECC bytes */
	ecc_value = ecc_readl(host->ecc, PR);

	ecc_code[0] = ecc_value & 0xFF;
	ecc_code[1] = (ecc_value >> 8) & 0xFF;

	/* get the last 2 ECC bytes */
	ecc_value = ecc_readl(host->ecc, NPR) & ATMEL_ECC_NPARITY;

	ecc_code[2] = ecc_value & 0xFF;
	ecc_code[3] = (ecc_value >> 8) & 0xFF;

	return 0;
}

/*
 * HW ECC read page function
 *
 * mtd:        mtd info structure
 * chip:       nand chip info structure
 * buf:        buffer to store read data
 * oob_required:    caller expects OOB data read to chip->oob_poi
 */
static int atmel_nand_read_page(struct mtd_info *mtd, struct nand_chip *chip,
				uint8_t *buf, int oob_required, int page)
{
	int eccsize = chip->ecc.size;
	int eccbytes = chip->ecc.bytes;
	uint32_t *eccpos = chip->ecc.layout->eccpos;
	uint8_t *p = buf;
	uint8_t *oob = chip->oob_poi;
	uint8_t *ecc_pos;
	int stat;
	unsigned int max_bitflips = 0;

	/*
	 * Errata: ALE is incorrectly wired up to the ECC controller
	 * on the AP7000, so it will include the address cycles in the
	 * ECC calculation.
	 *
	 * Workaround: Reset the parity registers before reading the
	 * actual data.
	 */
	if (cpu_is_at32ap7000()) {
		struct atmel_nand_host *host = chip->priv;
		ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
	}

	/* read the page */
	chip->read_buf(mtd, p, eccsize);

	/* move to ECC position if needed */
	if (eccpos[0] != 0) {
		/* This only works on large pages
		 * because the ECC controller waits for
		 * NAND_CMD_RNDOUTSTART after the
		 * NAND_CMD_RNDOUT.
		 * anyway, for small pages, the eccpos[0] == 0
		 */
		chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
				mtd->writesize + eccpos[0], -1);
	}

	/* the ECC controller needs to read the ECC just after the data */
	ecc_pos = oob + eccpos[0];
	chip->read_buf(mtd, ecc_pos, eccbytes);

	/* check if there's an error */
	stat = chip->ecc.correct(mtd, p, oob, NULL);

	if (stat < 0) {
		mtd->ecc_stats.failed++;
	} else {
		mtd->ecc_stats.corrected += stat;
		max_bitflips = max_t(unsigned int, max_bitflips, stat);
	}

	/* get back to oob start (end of page) */
	chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1);

	/* read the oob */
	chip->read_buf(mtd, oob, mtd->oobsize);

	return max_bitflips;
}

/*
 * HW ECC Correction
 *
 * function called after a read
 *
 * mtd:        MTD block structure
 * dat:        raw data read from the chip
 * read_ecc:   ECC from the chip (unused)
 * isnull:     unused
 *
 * Detect and correct a 1 bit error for a page
 */
static int atmel_nand_correct(struct mtd_info *mtd, u_char *dat,
		u_char *read_ecc, u_char *isnull)
{
	struct nand_chip *nand_chip = mtd->priv;
	struct atmel_nand_host *host = nand_chip->priv;
	unsigned int ecc_status;
	unsigned int ecc_word, ecc_bit;

	/* get the status from the Status Register */
	ecc_status = ecc_readl(host->ecc, SR);

	/* if there's no error */
	if (likely(!(ecc_status & ATMEL_ECC_RECERR)))
		return 0;

	/* get error bit offset (4 bits) */
	ecc_bit = ecc_readl(host->ecc, PR) & ATMEL_ECC_BITADDR;
	/* get word address (12 bits) */
	ecc_word = ecc_readl(host->ecc, PR) & ATMEL_ECC_WORDADDR;
	ecc_word >>= 4;

	/* if there are multiple errors */
	if (ecc_status & ATMEL_ECC_MULERR) {
		/* check if it is a freshly erased block
		 * (filled with 0xff) */
		if ((ecc_bit == ATMEL_ECC_BITADDR)
				&& (ecc_word == (ATMEL_ECC_WORDADDR >> 4))) {
			/* the block has just been erased, return OK */
			return 0;
		}
		/* it doesn't seems to be a freshly
		 * erased block.
		 * We can't correct so many errors */
		dev_dbg(host->dev, "atmel_nand : multiple errors detected."
				" Unable to correct.\n");
		return -EIO;
	}

	/* if there's a single bit error : we can correct it */
	if (ecc_status & ATMEL_ECC_ECCERR) {
		/* there's nothing much to do here.
		 * the bit error is on the ECC itself.
		 */
		dev_dbg(host->dev, "atmel_nand : one bit error on ECC code."
				" Nothing to correct\n");
		return 0;
	}

	dev_dbg(host->dev, "atmel_nand : one bit error on data."
			" (word offset in the page :"
			" 0x%x bit offset : 0x%x)\n",
			ecc_word, ecc_bit);
	/* correct the error */
	if (nand_chip->options & NAND_BUSWIDTH_16) {
		/* 16 bits words */
		((unsigned short *) dat)[ecc_word] ^= (1 << ecc_bit);
	} else {
		/* 8 bits words */
		dat[ecc_word] ^= (1 << ecc_bit);
	}
	dev_dbg(host->dev, "atmel_nand : error corrected\n");
	return 1;
}

/*
 * Enable HW ECC : unused on most chips
 */
static void atmel_nand_hwctl(struct mtd_info *mtd, int mode)
{
	if (cpu_is_at32ap7000()) {
		struct nand_chip *nand_chip = mtd->priv;
		struct atmel_nand_host *host = nand_chip->priv;
		ecc_writel(host->ecc, CR, ATMEL_ECC_RST);
	}
}

#if defined(CONFIG_OF)
static int atmel_of_init_port(struct atmel_nand_host *host,
					 struct device_node *np)
{
	u32 val, table_offset;
	u32 offset[2];
	int ecc_mode;
	struct atmel_nand_data *board = &host->board;
	enum of_gpio_flags flags;

	if (of_property_read_u32(np, "atmel,nand-addr-offset", &val) == 0) {
		if (val >= 32) {
			dev_err(host->dev, "invalid addr-offset %u\n", val);
			return -EINVAL;
		}
		board->ale = val;
	}

	if (of_property_read_u32(np, "atmel,nand-cmd-offset", &val) == 0) {
		if (val >= 32) {
			dev_err(host->dev, "invalid cmd-offset %u\n", val);
			return -EINVAL;
		}
		board->cle = val;
	}

	ecc_mode = of_get_nand_ecc_mode(np);

	board->ecc_mode = ecc_mode < 0 ? NAND_ECC_SOFT : ecc_mode;

	board->on_flash_bbt = of_get_nand_on_flash_bbt(np);

	if (of_get_nand_bus_width(np) == 16)
		board->bus_width_16 = 1;

	board->rdy_pin = of_get_gpio_flags(np, 0, &flags);
	board->rdy_pin_active_low = (flags == OF_GPIO_ACTIVE_LOW);

	board->enable_pin = of_get_gpio(np, 1);
	board->det_pin = of_get_gpio(np, 2);

	host->has_pmecc = of_property_read_bool(np, "atmel,has-pmecc");

	if (!(board->ecc_mode == NAND_ECC_HW) || !host->has_pmecc)
		return 0;	/* Not using PMECC */

	/* use PMECC, get correction capability, sector size and lookup
	 * table offset.
	 */
	if (of_property_read_u32(np, "atmel,pmecc-cap", &val) != 0) {
		dev_err(host->dev, "Cannot decide PMECC Capability\n");
		return -EINVAL;
	} else if ((val != 2) && (val != 4) && (val != 8) && (val != 12) &&
	    (val != 24)) {
		dev_err(host->dev,
			"Unsupported PMECC correction capability: %d; should be 2, 4, 8, 12 or 24\n",
			val);
		return -EINVAL;
	}
	host->pmecc_corr_cap = (u8)val;

	if (of_property_read_u32(np, "atmel,pmecc-sector-size", &val) != 0) {
		dev_err(host->dev, "Cannot decide PMECC Sector Size\n");
		return -EINVAL;
	} else if ((val != 512) && (val != 1024)) {
		dev_err(host->dev,
			"Unsupported PMECC sector size: %d; should be 512 or 1024 bytes\n",
			val);
		return -EINVAL;
	}
	host->pmecc_sector_size = (u16)val;

	if (of_property_read_u32_array(np, "atmel,pmecc-lookup-table-offset",
			offset, 2) != 0) {
		dev_err(host->dev, "Cannot get PMECC lookup table offset\n");
		return -EINVAL;
	}
	table_offset = host->pmecc_sector_size == 512 ? offset[0] : offset[1];

	if (!table_offset) {
		dev_err(host->dev, "Invalid PMECC lookup table offset\n");
		return -EINVAL;
	}
	host->pmecc_lookup_table_offset = table_offset;

	return 0;
}
#else
static int atmel_of_init_port(struct atmel_nand_host *host,
					 struct device_node *np)
{
	return -EINVAL;
}
#endif

static int __init atmel_hw_nand_init_params(struct platform_device *pdev,
					 struct atmel_nand_host *host)
{
	struct mtd_info *mtd = &host->mtd;
	struct nand_chip *nand_chip = &host->nand_chip;
	struct resource		*regs;

	regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	if (!regs) {
		dev_err(host->dev,
			"Can't get I/O resource regs, use software ECC\n");
		nand_chip->ecc.mode = NAND_ECC_SOFT;
		return 0;
	}

	host->ecc = ioremap(regs->start, resource_size(regs));
	if (host->ecc == NULL) {
		dev_err(host->dev, "ioremap failed\n");
		return -EIO;
	}

	/* ECC is calculated for the whole page (1 step) */
	nand_chip->ecc.size = mtd->writesize;

	/* set ECC page size and oob layout */
	switch (mtd->writesize) {
	case 512:
		nand_chip->ecc.layout = &atmel_oobinfo_small;
		ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_528);
		break;
	case 1024:
		nand_chip->ecc.layout = &atmel_oobinfo_large;
		ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_1056);
		break;
	case 2048:
		nand_chip->ecc.layout = &atmel_oobinfo_large;
		ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_2112);
		break;
	case 4096:
		nand_chip->ecc.layout = &atmel_oobinfo_large;
		ecc_writel(host->ecc, MR, ATMEL_ECC_PAGESIZE_4224);
		break;
	default:
		/* page size not handled by HW ECC */
		/* switching back to soft ECC */
		nand_chip->ecc.mode = NAND_ECC_SOFT;
		return 0;
	}

	/* set up for HW ECC */
	nand_chip->ecc.calculate = atmel_nand_calculate;
	nand_chip->ecc.correct = atmel_nand_correct;
	nand_chip->ecc.hwctl = atmel_nand_hwctl;
	nand_chip->ecc.read_page = atmel_nand_read_page;
	nand_chip->ecc.bytes = 4;
	nand_chip->ecc.strength = 1;

	return 0;
}

/*
 * Probe for the NAND device.
 */
static int __init atmel_nand_probe(struct platform_device *pdev)
{
	struct atmel_nand_host *host;
	struct mtd_info *mtd;
	struct nand_chip *nand_chip;
	struct resource *mem;
	struct mtd_part_parser_data ppdata = {};
	int res;

	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!mem) {
		printk(KERN_ERR "atmel_nand: can't get I/O resource mem\n");
		return -ENXIO;
	}

	/* Allocate memory for the device structure (and zero it) */
	host = kzalloc(sizeof(struct atmel_nand_host), GFP_KERNEL);
	if (!host) {
		printk(KERN_ERR "atmel_nand: failed to allocate device structure.\n");
		return -ENOMEM;
	}

	host->io_phys = (dma_addr_t)mem->start;

	host->io_base = ioremap(mem->start, resource_size(mem));
	if (host->io_base == NULL) {
		printk(KERN_ERR "atmel_nand: ioremap failed\n");
		res = -EIO;
		goto err_nand_ioremap;
	}

	mtd = &host->mtd;
	nand_chip = &host->nand_chip;
	host->dev = &pdev->dev;
	if (pdev->dev.of_node) {
		res = atmel_of_init_port(host, pdev->dev.of_node);
		if (res)
			goto err_ecc_ioremap;
	} else {
		memcpy(&host->board, pdev->dev.platform_data,
		       sizeof(struct atmel_nand_data));
	}

	nand_chip->priv = host;		/* link the private data structures */
	mtd->priv = nand_chip;
	mtd->owner = THIS_MODULE;

	/* Set address of NAND IO lines */
	nand_chip->IO_ADDR_R = host->io_base;
	nand_chip->IO_ADDR_W = host->io_base;
	nand_chip->cmd_ctrl = atmel_nand_cmd_ctrl;

	if (gpio_is_valid(host->board.rdy_pin)) {
		res = gpio_request(host->board.rdy_pin, "nand_rdy");
		if (res < 0) {
			dev_err(&pdev->dev,
				"can't request rdy gpio %d\n",
				host->board.rdy_pin);
			goto err_ecc_ioremap;
		}

		res = gpio_direction_input(host->board.rdy_pin);
		if (res < 0) {
			dev_err(&pdev->dev,
				"can't request input direction rdy gpio %d\n",
				host->board.rdy_pin);
			goto err_ecc_ioremap;
		}

		nand_chip->dev_ready = atmel_nand_device_ready;
	}

	if (gpio_is_valid(host->board.enable_pin)) {
		res = gpio_request(host->board.enable_pin, "nand_enable");
		if (res < 0) {
			dev_err(&pdev->dev,
				"can't request enable gpio %d\n",
				host->board.enable_pin);
			goto err_ecc_ioremap;
		}

		res = gpio_direction_output(host->board.enable_pin, 1);
		if (res < 0) {
			dev_err(&pdev->dev,
				"can't request output direction enable gpio %d\n",
				host->board.enable_pin);
			goto err_ecc_ioremap;
		}
	}

	nand_chip->ecc.mode = host->board.ecc_mode;
	nand_chip->chip_delay = 20;		/* 20us command delay time */

	if (host->board.bus_width_16)	/* 16-bit bus width */
		nand_chip->options |= NAND_BUSWIDTH_16;

	nand_chip->read_buf = atmel_read_buf;
	nand_chip->write_buf = atmel_write_buf;

	platform_set_drvdata(pdev, host);
	atmel_nand_enable(host);

	if (gpio_is_valid(host->board.det_pin)) {
		res = gpio_request(host->board.det_pin, "nand_det");
		if (res < 0) {
			dev_err(&pdev->dev,
				"can't request det gpio %d\n",
				host->board.det_pin);
			goto err_no_card;
		}

		res = gpio_direction_input(host->board.det_pin);
		if (res < 0) {
			dev_err(&pdev->dev,
				"can't request input direction det gpio %d\n",
				host->board.det_pin);
			goto err_no_card;
		}

		if (gpio_get_value(host->board.det_pin)) {
			printk(KERN_INFO "No SmartMedia card inserted.\n");
			res = -ENXIO;
			goto err_no_card;
		}
	}

	if (host->board.on_flash_bbt || on_flash_bbt) {
		printk(KERN_INFO "atmel_nand: Use On Flash BBT\n");
		nand_chip->bbt_options |= NAND_BBT_USE_FLASH;
	}

	if (!cpu_has_dma())
		use_dma = 0;

	if (use_dma) {
		dma_cap_mask_t mask;

		dma_cap_zero(mask);
		dma_cap_set(DMA_MEMCPY, mask);
		host->dma_chan = dma_request_channel(mask, NULL, NULL);
		if (!host->dma_chan) {
			dev_err(host->dev, "Failed to request DMA channel\n");
			use_dma = 0;
		}
	}
	if (use_dma)
		dev_info(host->dev, "Using %s for DMA transfers.\n",
					dma_chan_name(host->dma_chan));
	else
		dev_info(host->dev, "No DMA support for NAND access.\n");

	/* first scan to find the device and get the page size */
	if (nand_scan_ident(mtd, 1, NULL)) {
		res = -ENXIO;
		goto err_scan_ident;
	}

	if (nand_chip->ecc.mode == NAND_ECC_HW) {
		if (host->has_pmecc)
			res = atmel_pmecc_nand_init_params(pdev, host);
		else
			res = atmel_hw_nand_init_params(pdev, host);

		if (res != 0)
			goto err_hw_ecc;
	}

	/* second phase scan */
	if (nand_scan_tail(mtd)) {
		res = -ENXIO;
		goto err_scan_tail;
	}

	mtd->name = "atmel_nand";
	ppdata.of_node = pdev->dev.of_node;
	res = mtd_device_parse_register(mtd, NULL, &ppdata,
			host->board.parts, host->board.num_parts);
	if (!res)
		return res;

err_scan_tail:
	if (host->has_pmecc && host->nand_chip.ecc.mode == NAND_ECC_HW) {
		pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
		pmecc_data_free(host);
	}
	if (host->ecc)
		iounmap(host->ecc);
	if (host->pmerrloc_base)
		iounmap(host->pmerrloc_base);
	if (host->pmecc_rom_base)
		iounmap(host->pmecc_rom_base);
err_hw_ecc:
err_scan_ident:
err_no_card:
	atmel_nand_disable(host);
	platform_set_drvdata(pdev, NULL);
	if (host->dma_chan)
		dma_release_channel(host->dma_chan);
err_ecc_ioremap:
	iounmap(host->io_base);
err_nand_ioremap:
	kfree(host);
	return res;
}

/*
 * Remove a NAND device.
 */
static int __exit atmel_nand_remove(struct platform_device *pdev)
{
	struct atmel_nand_host *host = platform_get_drvdata(pdev);
	struct mtd_info *mtd = &host->mtd;

	nand_release(mtd);

	atmel_nand_disable(host);

	if (host->has_pmecc && host->nand_chip.ecc.mode == NAND_ECC_HW) {
		pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
		pmerrloc_writel(host->pmerrloc_base, ELDIS,
				PMERRLOC_DISABLE);
		pmecc_data_free(host);
	}

	if (gpio_is_valid(host->board.det_pin))
		gpio_free(host->board.det_pin);

	if (gpio_is_valid(host->board.enable_pin))
		gpio_free(host->board.enable_pin);

	if (gpio_is_valid(host->board.rdy_pin))
		gpio_free(host->board.rdy_pin);

	if (host->ecc)
		iounmap(host->ecc);
	if (host->pmecc_rom_base)
		iounmap(host->pmecc_rom_base);
	if (host->pmerrloc_base)
		iounmap(host->pmerrloc_base);

	if (host->dma_chan)
		dma_release_channel(host->dma_chan);

	iounmap(host->io_base);
	kfree(host);

	return 0;
}

#if defined(CONFIG_OF)
static const struct of_device_id atmel_nand_dt_ids[] = {
	{ .compatible = "atmel,at91rm9200-nand" },
	{ /* sentinel */ }
};

MODULE_DEVICE_TABLE(of, atmel_nand_dt_ids);
#endif

static struct platform_driver atmel_nand_driver = {
	.remove		= __exit_p(atmel_nand_remove),
	.driver		= {
		.name	= "atmel_nand",
		.owner	= THIS_MODULE,
		.of_match_table	= of_match_ptr(atmel_nand_dt_ids),
	},
};

static int __init atmel_nand_init(void)
{
	return platform_driver_probe(&atmel_nand_driver, atmel_nand_probe);
}


static void __exit atmel_nand_exit(void)
{
	platform_driver_unregister(&atmel_nand_driver);
}


module_init(atmel_nand_init);
module_exit(atmel_nand_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Rick Bronson");
MODULE_DESCRIPTION("NAND/SmartMedia driver for AT91 / AVR32");
MODULE_ALIAS("platform:atmel_nand");