drivers/mtd/nand/pxa3xx_nand.c

/*
 * drivers/mtd/nand/pxa3xx_nand.c
 *
 * Copyright © 2005 Intel Corporation
 * Copyright © 2006 Marvell International Ltd.
 *
 * 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.
 *
 * See Documentation/mtd/nand/pxa3xx-nand.txt for more details.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dma/pxa-dma.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_data/mtd-nand-pxa3xx.h>

#define	CHIP_DELAY_TIMEOUT	msecs_to_jiffies(200)
#define NAND_STOP_DELAY		msecs_to_jiffies(40)
#define PAGE_CHUNK_SIZE		(2048)

/*
 * Define a buffer size for the initial command that detects the flash device:
 * STATUS, READID and PARAM.
 * ONFI param page is 256 bytes, and there are three redundant copies
 * to be read. JEDEC param page is 512 bytes, and there are also three
 * redundant copies to be read.
 * Hence this buffer should be at least 512 x 3. Let's pick 2048.
 */
#define INIT_BUFFER_SIZE	2048

/* registers and bit definitions */
#define NDCR		(0x00) /* Control register */
#define NDTR0CS0	(0x04) /* Timing Parameter 0 for CS0 */
#define NDTR1CS0	(0x0C) /* Timing Parameter 1 for CS0 */
#define NDSR		(0x14) /* Status Register */
#define NDPCR		(0x18) /* Page Count Register */
#define NDBDR0		(0x1C) /* Bad Block Register 0 */
#define NDBDR1		(0x20) /* Bad Block Register 1 */
#define NDECCCTRL	(0x28) /* ECC control */
#define NDDB		(0x40) /* Data Buffer */
#define NDCB0		(0x48) /* Command Buffer0 */
#define NDCB1		(0x4C) /* Command Buffer1 */
#define NDCB2		(0x50) /* Command Buffer2 */

#define NDCR_SPARE_EN		(0x1 << 31)
#define NDCR_ECC_EN		(0x1 << 30)
#define NDCR_DMA_EN		(0x1 << 29)
#define NDCR_ND_RUN		(0x1 << 28)
#define NDCR_DWIDTH_C		(0x1 << 27)
#define NDCR_DWIDTH_M		(0x1 << 26)
#define NDCR_PAGE_SZ		(0x1 << 24)
#define NDCR_NCSX		(0x1 << 23)
#define NDCR_ND_MODE		(0x3 << 21)
#define NDCR_NAND_MODE   	(0x0)
#define NDCR_CLR_PG_CNT		(0x1 << 20)
#define NFCV1_NDCR_ARB_CNTL	(0x1 << 19)
#define NFCV2_NDCR_STOP_ON_UNCOR	(0x1 << 19)
#define NDCR_RD_ID_CNT_MASK	(0x7 << 16)
#define NDCR_RD_ID_CNT(x)	(((x) << 16) & NDCR_RD_ID_CNT_MASK)

#define NDCR_RA_START		(0x1 << 15)
#define NDCR_PG_PER_BLK		(0x1 << 14)
#define NDCR_ND_ARB_EN		(0x1 << 12)
#define NDCR_INT_MASK           (0xFFF)

#define NDSR_MASK		(0xfff)
#define NDSR_ERR_CNT_OFF	(16)
#define NDSR_ERR_CNT_MASK       (0x1f)
#define NDSR_ERR_CNT(sr)	((sr >> NDSR_ERR_CNT_OFF) & NDSR_ERR_CNT_MASK)
#define NDSR_RDY                (0x1 << 12)
#define NDSR_FLASH_RDY          (0x1 << 11)
#define NDSR_CS0_PAGED		(0x1 << 10)
#define NDSR_CS1_PAGED		(0x1 << 9)
#define NDSR_CS0_CMDD		(0x1 << 8)
#define NDSR_CS1_CMDD		(0x1 << 7)
#define NDSR_CS0_BBD		(0x1 << 6)
#define NDSR_CS1_BBD		(0x1 << 5)
#define NDSR_UNCORERR		(0x1 << 4)
#define NDSR_CORERR		(0x1 << 3)
#define NDSR_WRDREQ		(0x1 << 2)
#define NDSR_RDDREQ		(0x1 << 1)
#define NDSR_WRCMDREQ		(0x1)

#define NDCB0_LEN_OVRD		(0x1 << 28)
#define NDCB0_ST_ROW_EN         (0x1 << 26)
#define NDCB0_AUTO_RS		(0x1 << 25)
#define NDCB0_CSEL		(0x1 << 24)
#define NDCB0_EXT_CMD_TYPE_MASK	(0x7 << 29)
#define NDCB0_EXT_CMD_TYPE(x)	(((x) << 29) & NDCB0_EXT_CMD_TYPE_MASK)
#define NDCB0_CMD_TYPE_MASK	(0x7 << 21)
#define NDCB0_CMD_TYPE(x)	(((x) << 21) & NDCB0_CMD_TYPE_MASK)
#define NDCB0_NC		(0x1 << 20)
#define NDCB0_DBC		(0x1 << 19)
#define NDCB0_ADDR_CYC_MASK	(0x7 << 16)
#define NDCB0_ADDR_CYC(x)	(((x) << 16) & NDCB0_ADDR_CYC_MASK)
#define NDCB0_CMD2_MASK		(0xff << 8)
#define NDCB0_CMD1_MASK		(0xff)
#define NDCB0_ADDR_CYC_SHIFT	(16)

#define EXT_CMD_TYPE_DISPATCH	6 /* Command dispatch */
#define EXT_CMD_TYPE_NAKED_RW	5 /* Naked read or Naked write */
#define EXT_CMD_TYPE_READ	4 /* Read */
#define EXT_CMD_TYPE_DISP_WR	4 /* Command dispatch with write */
#define EXT_CMD_TYPE_FINAL	3 /* Final command */
#define EXT_CMD_TYPE_LAST_RW	1 /* Last naked read/write */
#define EXT_CMD_TYPE_MONO	0 /* Monolithic read/write */

/*
 * This should be large enough to read 'ONFI' and 'JEDEC'.
 * Let's use 7 bytes, which is the maximum ID count supported
 * by the controller (see NDCR_RD_ID_CNT_MASK).
 */
#define READ_ID_BYTES		7

/* macros for registers read/write */
#define nand_writel(info, off, val)					\
	do {								\
		dev_vdbg(&info->pdev->dev,				\
			 "%s():%d nand_writel(0x%x, 0x%04x)\n",		\
			 __func__, __LINE__, (val), (off));		\
		writel_relaxed((val), (info)->mmio_base + (off));	\
	} while (0)

#define nand_readl(info, off)						\
	({								\
		unsigned int _v;					\
		_v = readl_relaxed((info)->mmio_base + (off));		\
		dev_vdbg(&info->pdev->dev,				\
			 "%s():%d nand_readl(0x%04x) = 0x%x\n",		\
			 __func__, __LINE__, (off), _v);		\
		_v;							\
	})

/* error code and state */
enum {
	ERR_NONE	= 0,
	ERR_DMABUSERR	= -1,
	ERR_SENDCMD	= -2,
	ERR_UNCORERR	= -3,
	ERR_BBERR	= -4,
	ERR_CORERR	= -5,
};

enum {
	STATE_IDLE = 0,
	STATE_PREPARED,
	STATE_CMD_HANDLE,
	STATE_DMA_READING,
	STATE_DMA_WRITING,
	STATE_DMA_DONE,
	STATE_PIO_READING,
	STATE_PIO_WRITING,
	STATE_CMD_DONE,
	STATE_READY,
};

enum pxa3xx_nand_variant {
	PXA3XX_NAND_VARIANT_PXA,
	PXA3XX_NAND_VARIANT_ARMADA370,
};

struct pxa3xx_nand_host {
	struct nand_chip	chip;
	void			*info_data;

	/* page size of attached chip */
	int			use_ecc;
	int			cs;

	/* calculated from pxa3xx_nand_flash data */
	unsigned int		col_addr_cycles;
	unsigned int		row_addr_cycles;
};

struct pxa3xx_nand_info {
	struct nand_hw_control	controller;
	struct platform_device	 *pdev;

	struct clk		*clk;
	void __iomem		*mmio_base;
	unsigned long		mmio_phys;
	struct completion	cmd_complete, dev_ready;

	unsigned int 		buf_start;
	unsigned int		buf_count;
	unsigned int		buf_size;
	unsigned int		data_buff_pos;
	unsigned int		oob_buff_pos;

	/* DMA information */
	struct scatterlist	sg;
	enum dma_data_direction	dma_dir;
	struct dma_chan		*dma_chan;
	dma_cookie_t		dma_cookie;
	int			drcmr_dat;

	unsigned char		*data_buff;
	unsigned char		*oob_buff;
	dma_addr_t 		data_buff_phys;
	int 			data_dma_ch;

	struct pxa3xx_nand_host *host[NUM_CHIP_SELECT];
	unsigned int		state;

	/*
	 * This driver supports NFCv1 (as found in PXA SoC)
	 * and NFCv2 (as found in Armada 370/XP SoC).
	 */
	enum pxa3xx_nand_variant variant;

	int			cs;
	int			use_ecc;	/* use HW ECC ? */
	int			ecc_bch;	/* using BCH ECC? */
	int			use_dma;	/* use DMA ? */
	int			use_spare;	/* use spare ? */
	int			need_wait;

	/* Amount of real data per full chunk */
	unsigned int		chunk_size;

	/* Amount of spare data per full chunk */
	unsigned int		spare_size;

	/* Number of full chunks (i.e chunk_size + spare_size) */
	unsigned int            nfullchunks;

	/*
	 * Total number of chunks. If equal to nfullchunks, then there
	 * are only full chunks. Otherwise, there is one last chunk of
	 * size (last_chunk_size + last_spare_size)
	 */
	unsigned int            ntotalchunks;

	/* Amount of real data in the last chunk */
	unsigned int		last_chunk_size;

	/* Amount of spare data in the last chunk */
	unsigned int		last_spare_size;

	unsigned int		ecc_size;
	unsigned int		ecc_err_cnt;
	unsigned int		max_bitflips;
	int 			retcode;

	/*
	 * Variables only valid during command
	 * execution. step_chunk_size and step_spare_size is the
	 * amount of real data and spare data in the current
	 * chunk. cur_chunk is the current chunk being
	 * read/programmed.
	 */
	unsigned int		step_chunk_size;
	unsigned int		step_spare_size;
	unsigned int            cur_chunk;

	/* cached register value */
	uint32_t		reg_ndcr;
	uint32_t		ndtr0cs0;
	uint32_t		ndtr1cs0;

	/* generated NDCBx register values */
	uint32_t		ndcb0;
	uint32_t		ndcb1;
	uint32_t		ndcb2;
	uint32_t		ndcb3;
};

static bool use_dma = 1;
module_param(use_dma, bool, 0444);
MODULE_PARM_DESC(use_dma, "enable DMA for data transferring to/from NAND HW");

struct pxa3xx_nand_timing {
	unsigned int	tCH;  /* Enable signal hold time */
	unsigned int	tCS;  /* Enable signal setup time */
	unsigned int	tWH;  /* ND_nWE high duration */
	unsigned int	tWP;  /* ND_nWE pulse time */
	unsigned int	tRH;  /* ND_nRE high duration */
	unsigned int	tRP;  /* ND_nRE pulse width */
	unsigned int	tR;   /* ND_nWE high to ND_nRE low for read */
	unsigned int	tWHR; /* ND_nWE high to ND_nRE low for status read */
	unsigned int	tAR;  /* ND_ALE low to ND_nRE low delay */
};

struct pxa3xx_nand_flash {
	uint32_t	chip_id;
	unsigned int	flash_width;	/* Width of Flash memory (DWIDTH_M) */
	unsigned int	dfc_width;	/* Width of flash controller(DWIDTH_C) */
	struct pxa3xx_nand_timing *timing;	/* NAND Flash timing */
};

static struct pxa3xx_nand_timing timing[] = {
	{ 40, 80, 60, 100, 80, 100, 90000, 400, 40, },
	{ 10,  0, 20,  40, 30,  40, 11123, 110, 10, },
	{ 10, 25, 15,  25, 15,  30, 25000,  60, 10, },
	{ 10, 35, 15,  25, 15,  25, 25000,  60, 10, },
};

static struct pxa3xx_nand_flash builtin_flash_types[] = {
	{ 0x46ec, 16, 16, &timing[1] },
	{ 0xdaec,  8,  8, &timing[1] },
	{ 0xd7ec,  8,  8, &timing[1] },
	{ 0xa12c,  8,  8, &timing[2] },
	{ 0xb12c, 16, 16, &timing[2] },
	{ 0xdc2c,  8,  8, &timing[2] },
	{ 0xcc2c, 16, 16, &timing[2] },
	{ 0xba20, 16, 16, &timing[3] },
};

static int pxa3xx_ooblayout_ecc(struct mtd_info *mtd, int section,
				struct mtd_oob_region *oobregion)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	int nchunks = mtd->writesize / info->chunk_size;

	if (section >= nchunks)
		return -ERANGE;

	oobregion->offset = ((info->ecc_size + info->spare_size) * section) +
			    info->spare_size;
	oobregion->length = info->ecc_size;

	return 0;
}

static int pxa3xx_ooblayout_free(struct mtd_info *mtd, int section,
				 struct mtd_oob_region *oobregion)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	int nchunks = mtd->writesize / info->chunk_size;

	if (section >= nchunks)
		return -ERANGE;

	if (!info->spare_size)
		return 0;

	oobregion->offset = section * (info->ecc_size + info->spare_size);
	oobregion->length = info->spare_size;
	if (!section) {
		/*
		 * Bootrom looks in bytes 0 & 5 for bad blocks for the
		 * 4KB page / 4bit BCH combination.
		 */
		if (mtd->writesize == 4096 && info->chunk_size == 2048) {
			oobregion->offset += 6;
			oobregion->length -= 6;
		} else {
			oobregion->offset += 2;
			oobregion->length -= 2;
		}
	}

	return 0;
}

static const struct mtd_ooblayout_ops pxa3xx_ooblayout_ops = {
	.ecc = pxa3xx_ooblayout_ecc,
	.free = pxa3xx_ooblayout_free,
};

static u8 bbt_pattern[] = {'M', 'V', 'B', 'b', 't', '0' };
static u8 bbt_mirror_pattern[] = {'1', 't', 'b', 'B', 'V', 'M' };

static struct nand_bbt_descr bbt_main_descr = {
	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
		| NAND_BBT_2BIT | NAND_BBT_VERSION,
	.offs =	8,
	.len = 6,
	.veroffs = 14,
	.maxblocks = 8,		/* Last 8 blocks in each chip */
	.pattern = bbt_pattern
};

static struct nand_bbt_descr bbt_mirror_descr = {
	.options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE
		| NAND_BBT_2BIT | NAND_BBT_VERSION,
	.offs =	8,
	.len = 6,
	.veroffs = 14,
	.maxblocks = 8,		/* Last 8 blocks in each chip */
	.pattern = bbt_mirror_pattern
};

#define NDTR0_tCH(c)	(min((c), 7) << 19)
#define NDTR0_tCS(c)	(min((c), 7) << 16)
#define NDTR0_tWH(c)	(min((c), 7) << 11)
#define NDTR0_tWP(c)	(min((c), 7) << 8)
#define NDTR0_tRH(c)	(min((c), 7) << 3)
#define NDTR0_tRP(c)	(min((c), 7) << 0)

#define NDTR1_tR(c)	(min((c), 65535) << 16)
#define NDTR1_tWHR(c)	(min((c), 15) << 4)
#define NDTR1_tAR(c)	(min((c), 15) << 0)

/* convert nano-seconds to nand flash controller clock cycles */
#define ns2cycle(ns, clk)	(int)((ns) * (clk / 1000000) / 1000)

static const struct of_device_id pxa3xx_nand_dt_ids[] = {
	{
		.compatible = "marvell,pxa3xx-nand",
		.data       = (void *)PXA3XX_NAND_VARIANT_PXA,
	},
	{
		.compatible = "marvell,armada370-nand",
		.data       = (void *)PXA3XX_NAND_VARIANT_ARMADA370,
	},
	{}
};
MODULE_DEVICE_TABLE(of, pxa3xx_nand_dt_ids);

static enum pxa3xx_nand_variant
pxa3xx_nand_get_variant(struct platform_device *pdev)
{
	const struct of_device_id *of_id =
			of_match_device(pxa3xx_nand_dt_ids, &pdev->dev);
	if (!of_id)
		return PXA3XX_NAND_VARIANT_PXA;
	return (enum pxa3xx_nand_variant)of_id->data;
}

static void pxa3xx_nand_set_timing(struct pxa3xx_nand_host *host,
				   const struct pxa3xx_nand_timing *t)
{
	struct pxa3xx_nand_info *info = host->info_data;
	unsigned long nand_clk = clk_get_rate(info->clk);
	uint32_t ndtr0, ndtr1;

	ndtr0 = NDTR0_tCH(ns2cycle(t->tCH, nand_clk)) |
		NDTR0_tCS(ns2cycle(t->tCS, nand_clk)) |
		NDTR0_tWH(ns2cycle(t->tWH, nand_clk)) |
		NDTR0_tWP(ns2cycle(t->tWP, nand_clk)) |
		NDTR0_tRH(ns2cycle(t->tRH, nand_clk)) |
		NDTR0_tRP(ns2cycle(t->tRP, nand_clk));

	ndtr1 = NDTR1_tR(ns2cycle(t->tR, nand_clk)) |
		NDTR1_tWHR(ns2cycle(t->tWHR, nand_clk)) |
		NDTR1_tAR(ns2cycle(t->tAR, nand_clk));

	info->ndtr0cs0 = ndtr0;
	info->ndtr1cs0 = ndtr1;
	nand_writel(info, NDTR0CS0, ndtr0);
	nand_writel(info, NDTR1CS0, ndtr1);
}

static void pxa3xx_nand_set_sdr_timing(struct pxa3xx_nand_host *host,
				       const struct nand_sdr_timings *t)
{
	struct pxa3xx_nand_info *info = host->info_data;
	struct nand_chip *chip = &host->chip;
	unsigned long nand_clk = clk_get_rate(info->clk);
	uint32_t ndtr0, ndtr1;

	u32 tCH_min = DIV_ROUND_UP(t->tCH_min, 1000);
	u32 tCS_min = DIV_ROUND_UP(t->tCS_min, 1000);
	u32 tWH_min = DIV_ROUND_UP(t->tWH_min, 1000);
	u32 tWP_min = DIV_ROUND_UP(t->tWC_min - t->tWH_min, 1000);
	u32 tREH_min = DIV_ROUND_UP(t->tREH_min, 1000);
	u32 tRP_min = DIV_ROUND_UP(t->tRC_min - t->tREH_min, 1000);
	u32 tR = chip->chip_delay * 1000;
	u32 tWHR_min = DIV_ROUND_UP(t->tWHR_min, 1000);
	u32 tAR_min = DIV_ROUND_UP(t->tAR_min, 1000);

	/* fallback to a default value if tR = 0 */
	if (!tR)
		tR = 20000;

	ndtr0 = NDTR0_tCH(ns2cycle(tCH_min, nand_clk)) |
		NDTR0_tCS(ns2cycle(tCS_min, nand_clk)) |
		NDTR0_tWH(ns2cycle(tWH_min, nand_clk)) |
		NDTR0_tWP(ns2cycle(tWP_min, nand_clk)) |
		NDTR0_tRH(ns2cycle(tREH_min, nand_clk)) |
		NDTR0_tRP(ns2cycle(tRP_min, nand_clk));

	ndtr1 = NDTR1_tR(ns2cycle(tR, nand_clk)) |
		NDTR1_tWHR(ns2cycle(tWHR_min, nand_clk)) |
		NDTR1_tAR(ns2cycle(tAR_min, nand_clk));

	info->ndtr0cs0 = ndtr0;
	info->ndtr1cs0 = ndtr1;
	nand_writel(info, NDTR0CS0, ndtr0);
	nand_writel(info, NDTR1CS0, ndtr1);
}

static int pxa3xx_nand_init_timings_compat(struct pxa3xx_nand_host *host,
					   unsigned int *flash_width,
					   unsigned int *dfc_width)
{
	struct nand_chip *chip = &host->chip;
	struct pxa3xx_nand_info *info = host->info_data;
	const struct pxa3xx_nand_flash *f = NULL;
	struct mtd_info *mtd = nand_to_mtd(&host->chip);
	int i, id, ntypes;

	ntypes = ARRAY_SIZE(builtin_flash_types);

	chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);

	id = chip->read_byte(mtd);
	id |= chip->read_byte(mtd) << 0x8;

	for (i = 0; i < ntypes; i++) {
		f = &builtin_flash_types[i];

		if (f->chip_id == id)
			break;
	}

	if (i == ntypes) {
		dev_err(&info->pdev->dev, "Error: timings not found\n");
		return -EINVAL;
	}

	pxa3xx_nand_set_timing(host, f->timing);

	*flash_width = f->flash_width;
	*dfc_width = f->dfc_width;

	return 0;
}

static int pxa3xx_nand_init_timings_onfi(struct pxa3xx_nand_host *host,
					 int mode)
{
	const struct nand_sdr_timings *timings;

	mode = fls(mode) - 1;
	if (mode < 0)
		mode = 0;

	timings = onfi_async_timing_mode_to_sdr_timings(mode);
	if (IS_ERR(timings))
		return PTR_ERR(timings);

	pxa3xx_nand_set_sdr_timing(host, timings);

	return 0;
}

static int pxa3xx_nand_init(struct pxa3xx_nand_host *host)
{
	struct nand_chip *chip = &host->chip;
	struct pxa3xx_nand_info *info = host->info_data;
	unsigned int flash_width = 0, dfc_width = 0;
	int mode, err;

	mode = onfi_get_async_timing_mode(chip);
	if (mode == ONFI_TIMING_MODE_UNKNOWN) {
		err = pxa3xx_nand_init_timings_compat(host, &flash_width,
						      &dfc_width);
		if (err)
			return err;

		if (flash_width == 16) {
			info->reg_ndcr |= NDCR_DWIDTH_M;
			chip->options |= NAND_BUSWIDTH_16;
		}

		info->reg_ndcr |= (dfc_width == 16) ? NDCR_DWIDTH_C : 0;
	} else {
		err = pxa3xx_nand_init_timings_onfi(host, mode);
		if (err)
			return err;
	}

	return 0;
}

/**
 * NOTE: it is a must to set ND_RUN firstly, then write
 * command buffer, otherwise, it does not work.
 * We enable all the interrupt at the same time, and
 * let pxa3xx_nand_irq to handle all logic.
 */
static void pxa3xx_nand_start(struct pxa3xx_nand_info *info)
{
	uint32_t ndcr;

	ndcr = info->reg_ndcr;

	if (info->use_ecc) {
		ndcr |= NDCR_ECC_EN;
		if (info->ecc_bch)
			nand_writel(info, NDECCCTRL, 0x1);
	} else {
		ndcr &= ~NDCR_ECC_EN;
		if (info->ecc_bch)
			nand_writel(info, NDECCCTRL, 0x0);
	}

	if (info->use_dma)
		ndcr |= NDCR_DMA_EN;
	else
		ndcr &= ~NDCR_DMA_EN;

	if (info->use_spare)
		ndcr |= NDCR_SPARE_EN;
	else
		ndcr &= ~NDCR_SPARE_EN;

	ndcr |= NDCR_ND_RUN;

	/* clear status bits and run */
	nand_writel(info, NDSR, NDSR_MASK);
	nand_writel(info, NDCR, 0);
	nand_writel(info, NDCR, ndcr);
}

static void pxa3xx_nand_stop(struct pxa3xx_nand_info *info)
{
	uint32_t ndcr;
	int timeout = NAND_STOP_DELAY;

	/* wait RUN bit in NDCR become 0 */
	ndcr = nand_readl(info, NDCR);
	while ((ndcr & NDCR_ND_RUN) && (timeout-- > 0)) {
		ndcr = nand_readl(info, NDCR);
		udelay(1);
	}

	if (timeout <= 0) {
		ndcr &= ~NDCR_ND_RUN;
		nand_writel(info, NDCR, ndcr);
	}
	if (info->dma_chan)
		dmaengine_terminate_all(info->dma_chan);

	/* clear status bits */
	nand_writel(info, NDSR, NDSR_MASK);
}

static void __maybe_unused
enable_int(struct pxa3xx_nand_info *info, uint32_t int_mask)
{
	uint32_t ndcr;

	ndcr = nand_readl(info, NDCR);
	nand_writel(info, NDCR, ndcr & ~int_mask);
}

static void disable_int(struct pxa3xx_nand_info *info, uint32_t int_mask)
{
	uint32_t ndcr;

	ndcr = nand_readl(info, NDCR);
	nand_writel(info, NDCR, ndcr | int_mask);
}

static void drain_fifo(struct pxa3xx_nand_info *info, void *data, int len)
{
	if (info->ecc_bch) {
		u32 val;
		int ret;

		/*
		 * According to the datasheet, when reading from NDDB
		 * with BCH enabled, after each 32 bytes reads, we
		 * have to make sure that the NDSR.RDDREQ bit is set.
		 *
		 * Drain the FIFO 8 32 bits reads at a time, and skip
		 * the polling on the last read.
		 */
		while (len > 8) {
			ioread32_rep(info->mmio_base + NDDB, data, 8);

			ret = readl_relaxed_poll_timeout(info->mmio_base + NDSR, val,
							 val & NDSR_RDDREQ, 1000, 5000);
			if (ret) {
				dev_err(&info->pdev->dev,
					"Timeout on RDDREQ while draining the FIFO\n");
				return;
			}

			data += 32;
			len -= 8;
		}
	}

	ioread32_rep(info->mmio_base + NDDB, data, len);
}

static void handle_data_pio(struct pxa3xx_nand_info *info)
{
	switch (info->state) {
	case STATE_PIO_WRITING:
		if (info->step_chunk_size)
			writesl(info->mmio_base + NDDB,
				info->data_buff + info->data_buff_pos,
				DIV_ROUND_UP(info->step_chunk_size, 4));

		if (info->step_spare_size)
			writesl(info->mmio_base + NDDB,
				info->oob_buff + info->oob_buff_pos,
				DIV_ROUND_UP(info->step_spare_size, 4));
		break;
	case STATE_PIO_READING:
		if (info->step_chunk_size)
			drain_fifo(info,
				   info->data_buff + info->data_buff_pos,
				   DIV_ROUND_UP(info->step_chunk_size, 4));

		if (info->step_spare_size)
			drain_fifo(info,
				   info->oob_buff + info->oob_buff_pos,
				   DIV_ROUND_UP(info->step_spare_size, 4));
		break;
	default:
		dev_err(&info->pdev->dev, "%s: invalid state %d\n", __func__,
				info->state);
		BUG();
	}

	/* Update buffer pointers for multi-page read/write */
	info->data_buff_pos += info->step_chunk_size;
	info->oob_buff_pos += info->step_spare_size;
}

static void pxa3xx_nand_data_dma_irq(void *data)
{
	struct pxa3xx_nand_info *info = data;
	struct dma_tx_state state;
	enum dma_status status;

	status = dmaengine_tx_status(info->dma_chan, info->dma_cookie, &state);
	if (likely(status == DMA_COMPLETE)) {
		info->state = STATE_DMA_DONE;
	} else {
		dev_err(&info->pdev->dev, "DMA error on data channel\n");
		info->retcode = ERR_DMABUSERR;
	}
	dma_unmap_sg(info->dma_chan->device->dev, &info->sg, 1, info->dma_dir);

	nand_writel(info, NDSR, NDSR_WRDREQ | NDSR_RDDREQ);
	enable_int(info, NDCR_INT_MASK);
}

static void start_data_dma(struct pxa3xx_nand_info *info)
{
	enum dma_transfer_direction direction;
	struct dma_async_tx_descriptor *tx;

	switch (info->state) {
	case STATE_DMA_WRITING:
		info->dma_dir = DMA_TO_DEVICE;
		direction = DMA_MEM_TO_DEV;
		break;
	case STATE_DMA_READING:
		info->dma_dir = DMA_FROM_DEVICE;
		direction = DMA_DEV_TO_MEM;
		break;
	default:
		dev_err(&info->pdev->dev, "%s: invalid state %d\n", __func__,
				info->state);
		BUG();
	}
	info->sg.length = info->chunk_size;
	if (info->use_spare)
		info->sg.length += info->spare_size + info->ecc_size;
	dma_map_sg(info->dma_chan->device->dev, &info->sg, 1, info->dma_dir);

	tx = dmaengine_prep_slave_sg(info->dma_chan, &info->sg, 1, direction,
				     DMA_PREP_INTERRUPT);
	if (!tx) {
		dev_err(&info->pdev->dev, "prep_slave_sg() failed\n");
		return;
	}
	tx->callback = pxa3xx_nand_data_dma_irq;
	tx->callback_param = info;
	info->dma_cookie = dmaengine_submit(tx);
	dma_async_issue_pending(info->dma_chan);
	dev_dbg(&info->pdev->dev, "%s(dir=%d cookie=%x size=%u)\n",
		__func__, direction, info->dma_cookie, info->sg.length);
}

static irqreturn_t pxa3xx_nand_irq_thread(int irq, void *data)
{
	struct pxa3xx_nand_info *info = data;

	handle_data_pio(info);

	info->state = STATE_CMD_DONE;
	nand_writel(info, NDSR, NDSR_WRDREQ | NDSR_RDDREQ);

	return IRQ_HANDLED;
}

static irqreturn_t pxa3xx_nand_irq(int irq, void *devid)
{
	struct pxa3xx_nand_info *info = devid;
	unsigned int status, is_completed = 0, is_ready = 0;
	unsigned int ready, cmd_done;
	irqreturn_t ret = IRQ_HANDLED;

	if (info->cs == 0) {
		ready           = NDSR_FLASH_RDY;
		cmd_done        = NDSR_CS0_CMDD;
	} else {
		ready           = NDSR_RDY;
		cmd_done        = NDSR_CS1_CMDD;
	}

	status = nand_readl(info, NDSR);

	if (status & NDSR_UNCORERR)
		info->retcode = ERR_UNCORERR;
	if (status & NDSR_CORERR) {
		info->retcode = ERR_CORERR;
		if (info->variant == PXA3XX_NAND_VARIANT_ARMADA370 &&
		    info->ecc_bch)
			info->ecc_err_cnt = NDSR_ERR_CNT(status);
		else
			info->ecc_err_cnt = 1;

		/*
		 * Each chunk composing a page is corrected independently,
		 * and we need to store maximum number of corrected bitflips
		 * to return it to the MTD layer in ecc.read_page().
		 */
		info->max_bitflips = max_t(unsigned int,
					   info->max_bitflips,
					   info->ecc_err_cnt);
	}
	if (status & (NDSR_RDDREQ | NDSR_WRDREQ)) {
		/* whether use dma to transfer data */
		if (info->use_dma) {
			disable_int(info, NDCR_INT_MASK);
			info->state = (status & NDSR_RDDREQ) ?
				      STATE_DMA_READING : STATE_DMA_WRITING;
			start_data_dma(info);
			goto NORMAL_IRQ_EXIT;
		} else {
			info->state = (status & NDSR_RDDREQ) ?
				      STATE_PIO_READING : STATE_PIO_WRITING;
			ret = IRQ_WAKE_THREAD;
			goto NORMAL_IRQ_EXIT;
		}
	}
	if (status & cmd_done) {
		info->state = STATE_CMD_DONE;
		is_completed = 1;
	}
	if (status & ready) {
		info->state = STATE_READY;
		is_ready = 1;
	}

	/*
	 * Clear all status bit before issuing the next command, which
	 * can and will alter the status bits and will deserve a new
	 * interrupt on its own. This lets the controller exit the IRQ
	 */
	nand_writel(info, NDSR, status);

	if (status & NDSR_WRCMDREQ) {
		status &= ~NDSR_WRCMDREQ;
		info->state = STATE_CMD_HANDLE;

		/*
		 * Command buffer registers NDCB{0-2} (and optionally NDCB3)
		 * must be loaded by writing directly either 12 or 16
		 * bytes directly to NDCB0, four bytes at a time.
		 *
		 * Direct write access to NDCB1, NDCB2 and NDCB3 is ignored
		 * but each NDCBx register can be read.
		 */
		nand_writel(info, NDCB0, info->ndcb0);
		nand_writel(info, NDCB0, info->ndcb1);
		nand_writel(info, NDCB0, info->ndcb2);

		/* NDCB3 register is available in NFCv2 (Armada 370/XP SoC) */
		if (info->variant == PXA3XX_NAND_VARIANT_ARMADA370)
			nand_writel(info, NDCB0, info->ndcb3);
	}

	if (is_completed)
		complete(&info->cmd_complete);
	if (is_ready)
		complete(&info->dev_ready);
NORMAL_IRQ_EXIT:
	return ret;
}

static inline int is_buf_blank(uint8_t *buf, size_t len)
{
	for (; len > 0; len--)
		if (*buf++ != 0xff)
			return 0;
	return 1;
}

static void set_command_address(struct pxa3xx_nand_info *info,
		unsigned int page_size, uint16_t column, int page_addr)
{
	/* small page addr setting */
	if (page_size < PAGE_CHUNK_SIZE) {
		info->ndcb1 = ((page_addr & 0xFFFFFF) << 8)
				| (column & 0xFF);

		info->ndcb2 = 0;
	} else {
		info->ndcb1 = ((page_addr & 0xFFFF) << 16)
				| (column & 0xFFFF);

		if (page_addr & 0xFF0000)
			info->ndcb2 = (page_addr & 0xFF0000) >> 16;
		else
			info->ndcb2 = 0;
	}
}

static void prepare_start_command(struct pxa3xx_nand_info *info, int command)
{
	struct pxa3xx_nand_host *host = info->host[info->cs];
	struct mtd_info *mtd = nand_to_mtd(&host->chip);

	/* reset data and oob column point to handle data */
	info->buf_start		= 0;
	info->buf_count		= 0;
	info->data_buff_pos	= 0;
	info->oob_buff_pos	= 0;
	info->step_chunk_size   = 0;
	info->step_spare_size   = 0;
	info->cur_chunk         = 0;
	info->use_ecc		= 0;
	info->use_spare		= 1;
	info->retcode		= ERR_NONE;
	info->ecc_err_cnt	= 0;
	info->ndcb3		= 0;
	info->need_wait		= 0;

	switch (command) {
	case NAND_CMD_READ0:
	case NAND_CMD_PAGEPROG:
		info->use_ecc = 1;
		break;
	case NAND_CMD_PARAM:
		info->use_spare = 0;
		break;
	default:
		info->ndcb1 = 0;
		info->ndcb2 = 0;
		break;
	}

	/*
	 * If we are about to issue a read command, or about to set
	 * the write address, then clean the data buffer.
	 */
	if (command == NAND_CMD_READ0 ||
	    command == NAND_CMD_READOOB ||
	    command == NAND_CMD_SEQIN) {

		info->buf_count = mtd->writesize + mtd->oobsize;
		memset(info->data_buff, 0xFF, info->buf_count);
	}

}

static int prepare_set_command(struct pxa3xx_nand_info *info, int command,
		int ext_cmd_type, uint16_t column, int page_addr)
{
	int addr_cycle, exec_cmd;
	struct pxa3xx_nand_host *host;
	struct mtd_info *mtd;

	host = info->host[info->cs];
	mtd = nand_to_mtd(&host->chip);
	addr_cycle = 0;
	exec_cmd = 1;

	if (info->cs != 0)
		info->ndcb0 = NDCB0_CSEL;
	else
		info->ndcb0 = 0;

	if (command == NAND_CMD_SEQIN)
		exec_cmd = 0;

	addr_cycle = NDCB0_ADDR_CYC(host->row_addr_cycles
				    + host->col_addr_cycles);

	switch (command) {
	case NAND_CMD_READOOB:
	case NAND_CMD_READ0:
		info->buf_start = column;
		info->ndcb0 |= NDCB0_CMD_TYPE(0)
				| addr_cycle
				| NAND_CMD_READ0;

		if (command == NAND_CMD_READOOB)
			info->buf_start += mtd->writesize;

		if (info->cur_chunk < info->nfullchunks) {
			info->step_chunk_size = info->chunk_size;
			info->step_spare_size = info->spare_size;
		} else {
			info->step_chunk_size = info->last_chunk_size;
			info->step_spare_size = info->last_spare_size;
		}

		/*
		 * Multiple page read needs an 'extended command type' field,
		 * which is either naked-read or last-read according to the
		 * state.
		 */
		if (mtd->writesize == PAGE_CHUNK_SIZE) {
			info->ndcb0 |= NDCB0_DBC | (NAND_CMD_READSTART << 8);
		} else if (mtd->writesize > PAGE_CHUNK_SIZE) {
			info->ndcb0 |= NDCB0_DBC | (NAND_CMD_READSTART << 8)
					| NDCB0_LEN_OVRD
					| NDCB0_EXT_CMD_TYPE(ext_cmd_type);
			info->ndcb3 = info->step_chunk_size +
				info->step_spare_size;
		}

		set_command_address(info, mtd->writesize, column, page_addr);
		break;

	case NAND_CMD_SEQIN:

		info->buf_start = column;
		set_command_address(info, mtd->writesize, 0, page_addr);

		/*
		 * Multiple page programming needs to execute the initial
		 * SEQIN command that sets the page address.
		 */
		if (mtd->writesize > PAGE_CHUNK_SIZE) {
			info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
				| NDCB0_EXT_CMD_TYPE(ext_cmd_type)
				| addr_cycle
				| command;
			exec_cmd = 1;
		}
		break;

	case NAND_CMD_PAGEPROG:
		if (is_buf_blank(info->data_buff,
					(mtd->writesize + mtd->oobsize))) {
			exec_cmd = 0;
			break;
		}

		if (info->cur_chunk < info->nfullchunks) {
			info->step_chunk_size = info->chunk_size;
			info->step_spare_size = info->spare_size;
		} else {
			info->step_chunk_size = info->last_chunk_size;
			info->step_spare_size = info->last_spare_size;
		}

		/* Second command setting for large pages */
		if (mtd->writesize > PAGE_CHUNK_SIZE) {
			/*
			 * Multiple page write uses the 'extended command'
			 * field. This can be used to issue a command dispatch
			 * or a naked-write depending on the current stage.
			 */
			info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
					| NDCB0_LEN_OVRD
					| NDCB0_EXT_CMD_TYPE(ext_cmd_type);
			info->ndcb3 = info->step_chunk_size +
				      info->step_spare_size;

			/*
			 * This is the command dispatch that completes a chunked
			 * page program operation.
			 */
			if (info->cur_chunk == info->ntotalchunks) {
				info->ndcb0 = NDCB0_CMD_TYPE(0x1)
					| NDCB0_EXT_CMD_TYPE(ext_cmd_type)
					| command;
				info->ndcb1 = 0;
				info->ndcb2 = 0;
				info->ndcb3 = 0;
			}
		} else {
			info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
					| NDCB0_AUTO_RS
					| NDCB0_ST_ROW_EN
					| NDCB0_DBC
					| (NAND_CMD_PAGEPROG << 8)
					| NAND_CMD_SEQIN
					| addr_cycle;
		}
		break;

	case NAND_CMD_PARAM:
		info->buf_count = INIT_BUFFER_SIZE;
		info->ndcb0 |= NDCB0_CMD_TYPE(0)
				| NDCB0_ADDR_CYC(1)
				| NDCB0_LEN_OVRD
				| command;
		info->ndcb1 = (column & 0xFF);
		info->ndcb3 = INIT_BUFFER_SIZE;
		info->step_chunk_size = INIT_BUFFER_SIZE;
		break;

	case NAND_CMD_READID:
		info->buf_count = READ_ID_BYTES;
		info->ndcb0 |= NDCB0_CMD_TYPE(3)
				| NDCB0_ADDR_CYC(1)
				| command;
		info->ndcb1 = (column & 0xFF);

		info->step_chunk_size = 8;
		break;
	case NAND_CMD_STATUS:
		info->buf_count = 1;
		info->ndcb0 |= NDCB0_CMD_TYPE(4)
				| NDCB0_ADDR_CYC(1)
				| command;

		info->step_chunk_size = 8;
		break;

	case NAND_CMD_ERASE1:
		info->ndcb0 |= NDCB0_CMD_TYPE(2)
				| NDCB0_AUTO_RS
				| NDCB0_ADDR_CYC(3)
				| NDCB0_DBC
				| (NAND_CMD_ERASE2 << 8)
				| NAND_CMD_ERASE1;
		info->ndcb1 = page_addr;
		info->ndcb2 = 0;

		break;
	case NAND_CMD_RESET:
		info->ndcb0 |= NDCB0_CMD_TYPE(5)
				| command;

		break;

	case NAND_CMD_ERASE2:
		exec_cmd = 0;
		break;

	default:
		exec_cmd = 0;
		dev_err(&info->pdev->dev, "non-supported command %x\n",
				command);
		break;
	}

	return exec_cmd;
}

static void nand_cmdfunc(struct mtd_info *mtd, unsigned command,
			 int column, int page_addr)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	int exec_cmd;

	/*
	 * if this is a x16 device ,then convert the input
	 * "byte" address into a "word" address appropriate
	 * for indexing a word-oriented device
	 */
	if (info->reg_ndcr & NDCR_DWIDTH_M)
		column /= 2;

	/*
	 * There may be different NAND chip hooked to
	 * different chip select, so check whether
	 * chip select has been changed, if yes, reset the timing
	 */
	if (info->cs != host->cs) {
		info->cs = host->cs;
		nand_writel(info, NDTR0CS0, info->ndtr0cs0);
		nand_writel(info, NDTR1CS0, info->ndtr1cs0);
	}

	prepare_start_command(info, command);

	info->state = STATE_PREPARED;
	exec_cmd = prepare_set_command(info, command, 0, column, page_addr);

	if (exec_cmd) {
		init_completion(&info->cmd_complete);
		init_completion(&info->dev_ready);
		info->need_wait = 1;
		pxa3xx_nand_start(info);

		if (!wait_for_completion_timeout(&info->cmd_complete,
		    CHIP_DELAY_TIMEOUT)) {
			dev_err(&info->pdev->dev, "Wait time out!!!\n");
			/* Stop State Machine for next command cycle */
			pxa3xx_nand_stop(info);
		}
	}
	info->state = STATE_IDLE;
}

static void nand_cmdfunc_extended(struct mtd_info *mtd,
				  const unsigned command,
				  int column, int page_addr)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	int exec_cmd, ext_cmd_type;

	/*
	 * if this is a x16 device then convert the input
	 * "byte" address into a "word" address appropriate
	 * for indexing a word-oriented device
	 */
	if (info->reg_ndcr & NDCR_DWIDTH_M)
		column /= 2;

	/*
	 * There may be different NAND chip hooked to
	 * different chip select, so check whether
	 * chip select has been changed, if yes, reset the timing
	 */
	if (info->cs != host->cs) {
		info->cs = host->cs;
		nand_writel(info, NDTR0CS0, info->ndtr0cs0);
		nand_writel(info, NDTR1CS0, info->ndtr1cs0);
	}

	/* Select the extended command for the first command */
	switch (command) {
	case NAND_CMD_READ0:
	case NAND_CMD_READOOB:
		ext_cmd_type = EXT_CMD_TYPE_MONO;
		break;
	case NAND_CMD_SEQIN:
		ext_cmd_type = EXT_CMD_TYPE_DISPATCH;
		break;
	case NAND_CMD_PAGEPROG:
		ext_cmd_type = EXT_CMD_TYPE_NAKED_RW;
		break;
	default:
		ext_cmd_type = 0;
		break;
	}

	prepare_start_command(info, command);

	/*
	 * Prepare the "is ready" completion before starting a command
	 * transaction sequence. If the command is not executed the
	 * completion will be completed, see below.
	 *
	 * We can do that inside the loop because the command variable
	 * is invariant and thus so is the exec_cmd.
	 */
	info->need_wait = 1;
	init_completion(&info->dev_ready);
	do {
		info->state = STATE_PREPARED;

		exec_cmd = prepare_set_command(info, command, ext_cmd_type,
					       column, page_addr);
		if (!exec_cmd) {
			info->need_wait = 0;
			complete(&info->dev_ready);
			break;
		}

		init_completion(&info->cmd_complete);
		pxa3xx_nand_start(info);

		if (!wait_for_completion_timeout(&info->cmd_complete,
		    CHIP_DELAY_TIMEOUT)) {
			dev_err(&info->pdev->dev, "Wait time out!!!\n");
			/* Stop State Machine for next command cycle */
			pxa3xx_nand_stop(info);
			break;
		}

		/* Only a few commands need several steps */
		if (command != NAND_CMD_PAGEPROG &&
		    command != NAND_CMD_READ0    &&
		    command != NAND_CMD_READOOB)
			break;

		info->cur_chunk++;

		/* Check if the sequence is complete */
		if (info->cur_chunk == info->ntotalchunks && command != NAND_CMD_PAGEPROG)
			break;

		/*
		 * After a splitted program command sequence has issued
		 * the command dispatch, the command sequence is complete.
		 */
		if (info->cur_chunk == (info->ntotalchunks + 1) &&
		    command == NAND_CMD_PAGEPROG &&
		    ext_cmd_type == EXT_CMD_TYPE_DISPATCH)
			break;

		if (command == NAND_CMD_READ0 || command == NAND_CMD_READOOB) {
			/* Last read: issue a 'last naked read' */
			if (info->cur_chunk == info->ntotalchunks - 1)
				ext_cmd_type = EXT_CMD_TYPE_LAST_RW;
			else
				ext_cmd_type = EXT_CMD_TYPE_NAKED_RW;

		/*
		 * If a splitted program command has no more data to transfer,
		 * the command dispatch must be issued to complete.
		 */
		} else if (command == NAND_CMD_PAGEPROG &&
			   info->cur_chunk == info->ntotalchunks) {
				ext_cmd_type = EXT_CMD_TYPE_DISPATCH;
		}
	} while (1);

	info->state = STATE_IDLE;
}

static int pxa3xx_nand_write_page_hwecc(struct mtd_info *mtd,
		struct nand_chip *chip, const uint8_t *buf, int oob_required,
		int page)
{
	chip->write_buf(mtd, buf, mtd->writesize);
	chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);

	return 0;
}

static int pxa3xx_nand_read_page_hwecc(struct mtd_info *mtd,
		struct nand_chip *chip, uint8_t *buf, int oob_required,
		int page)
{
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;

	chip->read_buf(mtd, buf, mtd->writesize);
	chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);

	if (info->retcode == ERR_CORERR && info->use_ecc) {
		mtd->ecc_stats.corrected += info->ecc_err_cnt;

	} else if (info->retcode == ERR_UNCORERR) {
		/*
		 * for blank page (all 0xff), HW will calculate its ECC as
		 * 0, which is different from the ECC information within
		 * OOB, ignore such uncorrectable errors
		 */
		if (is_buf_blank(buf, mtd->writesize))
			info->retcode = ERR_NONE;
		else
			mtd->ecc_stats.failed++;
	}

	return info->max_bitflips;
}

static uint8_t pxa3xx_nand_read_byte(struct mtd_info *mtd)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	char retval = 0xFF;

	if (info->buf_start < info->buf_count)
		/* Has just send a new command? */
		retval = info->data_buff[info->buf_start++];

	return retval;
}

static u16 pxa3xx_nand_read_word(struct mtd_info *mtd)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	u16 retval = 0xFFFF;

	if (!(info->buf_start & 0x01) && info->buf_start < info->buf_count) {
		retval = *((u16 *)(info->data_buff+info->buf_start));
		info->buf_start += 2;
	}
	return retval;
}

static void pxa3xx_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	int real_len = min_t(size_t, len, info->buf_count - info->buf_start);

	memcpy(buf, info->data_buff + info->buf_start, real_len);
	info->buf_start += real_len;
}

static void pxa3xx_nand_write_buf(struct mtd_info *mtd,
		const uint8_t *buf, int len)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	int real_len = min_t(size_t, len, info->buf_count - info->buf_start);

	memcpy(info->data_buff + info->buf_start, buf, real_len);
	info->buf_start += real_len;
}

static void pxa3xx_nand_select_chip(struct mtd_info *mtd, int chip)
{
	return;
}

static int pxa3xx_nand_waitfunc(struct mtd_info *mtd, struct nand_chip *this)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;

	if (info->need_wait) {
		info->need_wait = 0;
		if (!wait_for_completion_timeout(&info->dev_ready,
		    CHIP_DELAY_TIMEOUT)) {
			dev_err(&info->pdev->dev, "Ready time out!!!\n");
			return NAND_STATUS_FAIL;
		}
	}

	/* pxa3xx_nand_send_command has waited for command complete */
	if (this->state == FL_WRITING || this->state == FL_ERASING) {
		if (info->retcode == ERR_NONE)
			return 0;
		else
			return NAND_STATUS_FAIL;
	}

	return NAND_STATUS_READY;
}

static int pxa3xx_nand_config_ident(struct pxa3xx_nand_info *info)
{
	struct pxa3xx_nand_host *host = info->host[info->cs];
	struct platform_device *pdev = info->pdev;
	struct pxa3xx_nand_platform_data *pdata = dev_get_platdata(&pdev->dev);
	const struct nand_sdr_timings *timings;

	/* Configure default flash values */
	info->chunk_size = PAGE_CHUNK_SIZE;
	info->reg_ndcr = 0x0; /* enable all interrupts */
	info->reg_ndcr |= (pdata->enable_arbiter) ? NDCR_ND_ARB_EN : 0;
	info->reg_ndcr |= NDCR_RD_ID_CNT(READ_ID_BYTES);
	info->reg_ndcr |= NDCR_SPARE_EN;

	/* use the common timing to make a try */
	timings = onfi_async_timing_mode_to_sdr_timings(0);
	if (IS_ERR(timings))
		return PTR_ERR(timings);

	pxa3xx_nand_set_sdr_timing(host, timings);
	return 0;
}

static void pxa3xx_nand_config_tail(struct pxa3xx_nand_info *info)
{
	struct pxa3xx_nand_host *host = info->host[info->cs];
	struct nand_chip *chip = &host->chip;
	struct mtd_info *mtd = nand_to_mtd(chip);

	info->reg_ndcr |= (host->col_addr_cycles == 2) ? NDCR_RA_START : 0;
	info->reg_ndcr |= (chip->page_shift == 6) ? NDCR_PG_PER_BLK : 0;
	info->reg_ndcr |= (mtd->writesize == 2048) ? NDCR_PAGE_SZ : 0;
}

static void pxa3xx_nand_detect_config(struct pxa3xx_nand_info *info)
{
	struct platform_device *pdev = info->pdev;
	struct pxa3xx_nand_platform_data *pdata = dev_get_platdata(&pdev->dev);
	uint32_t ndcr = nand_readl(info, NDCR);

	/* Set an initial chunk size */
	info->chunk_size = ndcr & NDCR_PAGE_SZ ? 2048 : 512;
	info->reg_ndcr = ndcr &
		~(NDCR_INT_MASK | NDCR_ND_ARB_EN | NFCV1_NDCR_ARB_CNTL);
	info->reg_ndcr |= (pdata->enable_arbiter) ? NDCR_ND_ARB_EN : 0;
	info->ndtr0cs0 = nand_readl(info, NDTR0CS0);
	info->ndtr1cs0 = nand_readl(info, NDTR1CS0);
}

static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
{
	struct platform_device *pdev = info->pdev;
	struct dma_slave_config	config;
	dma_cap_mask_t mask;
	struct pxad_param param;
	int ret;

	info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
	if (info->data_buff == NULL)
		return -ENOMEM;
	if (use_dma == 0)
		return 0;

	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
	if (ret)
		return ret;

	sg_init_one(&info->sg, info->data_buff, info->buf_size);
	dma_cap_zero(mask);
	dma_cap_set(DMA_SLAVE, mask);
	param.prio = PXAD_PRIO_LOWEST;
	param.drcmr = info->drcmr_dat;
	info->dma_chan = dma_request_slave_channel_compat(mask, pxad_filter_fn,
							  &param, &pdev->dev,
							  "data");
	if (!info->dma_chan) {
		dev_err(&pdev->dev, "unable to request data dma channel\n");
		return -ENODEV;
	}

	memset(&config, 0, sizeof(config));
	config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
	config.src_addr = info->mmio_phys + NDDB;
	config.dst_addr = info->mmio_phys + NDDB;
	config.src_maxburst = 32;
	config.dst_maxburst = 32;
	ret = dmaengine_slave_config(info->dma_chan, &config);
	if (ret < 0) {
		dev_err(&info->pdev->dev,
			"dma channel configuration failed: %d\n",
			ret);
		return ret;
	}

	/*
	 * Now that DMA buffers are allocated we turn on
	 * DMA proper for I/O operations.
	 */
	info->use_dma = 1;
	return 0;
}

static void pxa3xx_nand_free_buff(struct pxa3xx_nand_info *info)
{
	if (info->use_dma) {
		dmaengine_terminate_all(info->dma_chan);
		dma_release_channel(info->dma_chan);
	}
	kfree(info->data_buff);
}

static int pxa_ecc_init(struct pxa3xx_nand_info *info,
			struct mtd_info *mtd,
			int strength, int ecc_stepsize, int page_size)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct nand_ecc_ctrl *ecc = &chip->ecc;

	if (strength == 1 && ecc_stepsize == 512 && page_size == 2048) {
		info->nfullchunks = 1;
		info->ntotalchunks = 1;
		info->chunk_size = 2048;
		info->spare_size = 40;
		info->ecc_size = 24;
		ecc->mode = NAND_ECC_HW;
		ecc->size = 512;
		ecc->strength = 1;

	} else if (strength == 1 && ecc_stepsize == 512 && page_size == 512) {
		info->nfullchunks = 1;
		info->ntotalchunks = 1;
		info->chunk_size = 512;
		info->spare_size = 8;
		info->ecc_size = 8;
		ecc->mode = NAND_ECC_HW;
		ecc->size = 512;
		ecc->strength = 1;

	/*
	 * Required ECC: 4-bit correction per 512 bytes
	 * Select: 16-bit correction per 2048 bytes
	 */
	} else if (strength == 4 && ecc_stepsize == 512 && page_size == 2048) {
		info->ecc_bch = 1;
		info->nfullchunks = 1;
		info->ntotalchunks = 1;
		info->chunk_size = 2048;
		info->spare_size = 32;
		info->ecc_size = 32;
		ecc->mode = NAND_ECC_HW;
		ecc->size = info->chunk_size;
		mtd_set_ooblayout(mtd, &pxa3xx_ooblayout_ops);
		ecc->strength = 16;

	} else if (strength == 4 && ecc_stepsize == 512 && page_size == 4096) {
		info->ecc_bch = 1;
		info->nfullchunks = 2;
		info->ntotalchunks = 2;
		info->chunk_size = 2048;
		info->spare_size = 32;
		info->ecc_size = 32;
		ecc->mode = NAND_ECC_HW;
		ecc->size = info->chunk_size;
		mtd_set_ooblayout(mtd, &pxa3xx_ooblayout_ops);
		ecc->strength = 16;

	/*
	 * Required ECC: 8-bit correction per 512 bytes
	 * Select: 16-bit correction per 1024 bytes
	 */
	} else if (strength == 8 && ecc_stepsize == 512 && page_size == 4096) {
		info->ecc_bch = 1;
		info->nfullchunks = 4;
		info->ntotalchunks = 5;
		info->chunk_size = 1024;
		info->spare_size = 0;
		info->last_chunk_size = 0;
		info->last_spare_size = 64;
		info->ecc_size = 32;
		ecc->mode = NAND_ECC_HW;
		ecc->size = info->chunk_size;
		mtd_set_ooblayout(mtd, &pxa3xx_ooblayout_ops);
		ecc->strength = 16;
	} else {
		dev_err(&info->pdev->dev,
			"ECC strength %d at page size %d is not supported\n",
			strength, page_size);
		return -ENODEV;
	}

	dev_info(&info->pdev->dev, "ECC strength %d, ECC step size %d\n",
		 ecc->strength, ecc->size);
	return 0;
}

static int pxa3xx_nand_scan(struct mtd_info *mtd)
{
	struct nand_chip *chip = mtd_to_nand(mtd);
	struct pxa3xx_nand_host *host = nand_get_controller_data(chip);
	struct pxa3xx_nand_info *info = host->info_data;
	struct platform_device *pdev = info->pdev;
	struct pxa3xx_nand_platform_data *pdata = dev_get_platdata(&pdev->dev);
	int ret;
	uint16_t ecc_strength, ecc_step;

	if (pdata->keep_config) {
		pxa3xx_nand_detect_config(info);
	} else {
		ret = pxa3xx_nand_config_ident(info);
		if (ret)
			return ret;
	}

	if (info->reg_ndcr & NDCR_DWIDTH_M)
		chip->options |= NAND_BUSWIDTH_16;

	/* Device detection must be done with ECC disabled */
	if (info->variant == PXA3XX_NAND_VARIANT_ARMADA370)
		nand_writel(info, NDECCCTRL, 0x0);

	if (pdata->flash_bbt)
		chip->bbt_options |= NAND_BBT_USE_FLASH;

	chip->ecc.strength = pdata->ecc_strength;
	chip->ecc.size = pdata->ecc_step_size;

	ret = nand_scan_ident(mtd, 1, NULL);
	if (ret)
		return ret;

	if (!pdata->keep_config) {
		ret = pxa3xx_nand_init(host);
		if (ret) {
			dev_err(&info->pdev->dev, "Failed to init nand: %d\n",
				ret);
			return ret;
		}
	}

	if (chip->bbt_options & NAND_BBT_USE_FLASH) {
		/*
		 * We'll use a bad block table stored in-flash and don't
		 * allow writing the bad block marker to the flash.
		 */
		chip->bbt_options |= NAND_BBT_NO_OOB_BBM;
		chip->bbt_td = &bbt_main_descr;
		chip->bbt_md = &bbt_mirror_descr;
	}

	/*
	 * If the page size is bigger than the FIFO size, let's check
	 * we are given the right variant and then switch to the extended
	 * (aka splitted) command handling,
	 */
	if (mtd->writesize > PAGE_CHUNK_SIZE) {
		if (info->variant == PXA3XX_NAND_VARIANT_ARMADA370) {
			chip->cmdfunc = nand_cmdfunc_extended;
		} else {
			dev_err(&info->pdev->dev,
				"unsupported page size on this variant\n");
			return -ENODEV;
		}
	}

	ecc_strength = chip->ecc.strength;
	ecc_step = chip->ecc.size;
	if (!ecc_strength || !ecc_step) {
		ecc_strength = chip->ecc_strength_ds;
		ecc_step = chip->ecc_step_ds;
	}

	/* Set default ECC strength requirements on non-ONFI devices */
	if (ecc_strength < 1 && ecc_step < 1) {
		ecc_strength = 1;
		ecc_step = 512;
	}

	ret = pxa_ecc_init(info, mtd, ecc_strength,
			   ecc_step, mtd->writesize);
	if (ret)
		return ret;

	/* calculate addressing information */
	if (mtd->writesize >= 2048)
		host->col_addr_cycles = 2;
	else
		host->col_addr_cycles = 1;

	/* release the initial buffer */
	kfree(info->data_buff);

	/* allocate the real data + oob buffer */
	info->buf_size = mtd->writesize + mtd->oobsize;
	ret = pxa3xx_nand_init_buff(info);
	if (ret)
		return ret;
	info->oob_buff = info->data_buff + mtd->writesize;

	if ((mtd->size >> chip->page_shift) > 65536)
		host->row_addr_cycles = 3;
	else
		host->row_addr_cycles = 2;

	if (!pdata->keep_config)
		pxa3xx_nand_config_tail(info);

	return nand_scan_tail(mtd);
}

static int alloc_nand_resource(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct pxa3xx_nand_platform_data *pdata;
	struct pxa3xx_nand_info *info;
	struct pxa3xx_nand_host *host;
	struct nand_chip *chip = NULL;
	struct mtd_info *mtd;
	struct resource *r;
	int ret, irq, cs;

	pdata = dev_get_platdata(&pdev->dev);
	if (pdata->num_cs <= 0) {
		dev_err(&pdev->dev, "invalid number of chip selects\n");
		return -ENODEV;
	}

	info = devm_kzalloc(&pdev->dev,
			    sizeof(*info) + sizeof(*host) * pdata->num_cs,
			    GFP_KERNEL);
	if (!info)
		return -ENOMEM;

	info->pdev = pdev;
	info->variant = pxa3xx_nand_get_variant(pdev);
	for (cs = 0; cs < pdata->num_cs; cs++) {
		host = (void *)&info[1] + sizeof(*host) * cs;
		chip = &host->chip;
		nand_set_controller_data(chip, host);
		mtd = nand_to_mtd(chip);
		info->host[cs] = host;
		host->cs = cs;
		host->info_data = info;
		mtd->dev.parent = &pdev->dev;
		/* FIXME: all chips use the same device tree partitions */
		nand_set_flash_node(chip, np);

		nand_set_controller_data(chip, host);
		chip->ecc.read_page	= pxa3xx_nand_read_page_hwecc;
		chip->ecc.write_page	= pxa3xx_nand_write_page_hwecc;
		chip->controller        = &info->controller;
		chip->waitfunc		= pxa3xx_nand_waitfunc;
		chip->select_chip	= pxa3xx_nand_select_chip;
		chip->read_word		= pxa3xx_nand_read_word;
		chip->read_byte		= pxa3xx_nand_read_byte;
		chip->read_buf		= pxa3xx_nand_read_buf;
		chip->write_buf		= pxa3xx_nand_write_buf;
		chip->options		|= NAND_NO_SUBPAGE_WRITE;
		chip->cmdfunc		= nand_cmdfunc;
	}

	nand_hw_control_init(chip->controller);
	info->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(info->clk)) {
		ret = PTR_ERR(info->clk);
		dev_err(&pdev->dev, "failed to get nand clock: %d\n", ret);
		return ret;
	}
	ret = clk_prepare_enable(info->clk);
	if (ret < 0)
		return ret;

	if (!np && use_dma) {
		r = platform_get_resource(pdev, IORESOURCE_DMA, 0);
		if (r == NULL) {
			dev_err(&pdev->dev,
				"no resource defined for data DMA\n");
			ret = -ENXIO;
			goto fail_disable_clk;
		}
		info->drcmr_dat = r->start;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(&pdev->dev, "no IRQ resource defined\n");
		ret = -ENXIO;
		goto fail_disable_clk;
	}

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	info->mmio_base = devm_ioremap_resource(&pdev->dev, r);
	if (IS_ERR(info->mmio_base)) {
		ret = PTR_ERR(info->mmio_base);
		dev_err(&pdev->dev, "failed to map register space: %d\n", ret);
		goto fail_disable_clk;
	}
	info->mmio_phys = r->start;

	/* Allocate a buffer to allow flash detection */
	info->buf_size = INIT_BUFFER_SIZE;
	info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
	if (info->data_buff == NULL) {
		ret = -ENOMEM;
		goto fail_disable_clk;
	}

	/* initialize all interrupts to be disabled */
	disable_int(info, NDSR_MASK);

	ret = request_threaded_irq(irq, pxa3xx_nand_irq,
				   pxa3xx_nand_irq_thread, IRQF_ONESHOT,
				   pdev->name, info);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to request IRQ: %d\n", ret);
		goto fail_free_buf;
	}

	platform_set_drvdata(pdev, info);

	return 0;

fail_free_buf:
	free_irq(irq, info);
	kfree(info->data_buff);
fail_disable_clk:
	clk_disable_unprepare(info->clk);
	return ret;
}

static int pxa3xx_nand_remove(struct platform_device *pdev)
{
	struct pxa3xx_nand_info *info = platform_get_drvdata(pdev);
	struct pxa3xx_nand_platform_data *pdata;
	int irq, cs;

	if (!info)
		return 0;

	pdata = dev_get_platdata(&pdev->dev);

	irq = platform_get_irq(pdev, 0);
	if (irq >= 0)
		free_irq(irq, info);
	pxa3xx_nand_free_buff(info);

	/*
	 * In the pxa3xx case, the DFI bus is shared between the SMC and NFC.
	 * In order to prevent a lockup of the system bus, the DFI bus
	 * arbitration is granted to SMC upon driver removal. This is done by
	 * setting the x_ARB_CNTL bit, which also prevents the NAND to have
	 * access to the bus anymore.
	 */
	nand_writel(info, NDCR,
		    (nand_readl(info, NDCR) & ~NDCR_ND_ARB_EN) |
		    NFCV1_NDCR_ARB_CNTL);
	clk_disable_unprepare(info->clk);

	for (cs = 0; cs < pdata->num_cs; cs++)
		nand_release(nand_to_mtd(&info->host[cs]->chip));
	return 0;
}

static int pxa3xx_nand_probe_dt(struct platform_device *pdev)
{
	struct pxa3xx_nand_platform_data *pdata;
	struct device_node *np = pdev->dev.of_node;
	const struct of_device_id *of_id =
			of_match_device(pxa3xx_nand_dt_ids, &pdev->dev);

	if (!of_id)
		return 0;

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

	if (of_get_property(np, "marvell,nand-enable-arbiter", NULL))
		pdata->enable_arbiter = 1;
	if (of_get_property(np, "marvell,nand-keep-config", NULL))
		pdata->keep_config = 1;
	of_property_read_u32(np, "num-cs", &pdata->num_cs);

	pdev->dev.platform_data = pdata;

	return 0;
}

static int pxa3xx_nand_probe(struct platform_device *pdev)
{
	struct pxa3xx_nand_platform_data *pdata;
	struct pxa3xx_nand_info *info;
	int ret, cs, probe_success, dma_available;

	dma_available = IS_ENABLED(CONFIG_ARM) &&
		(IS_ENABLED(CONFIG_ARCH_PXA) || IS_ENABLED(CONFIG_ARCH_MMP));
	if (use_dma && !dma_available) {
		use_dma = 0;
		dev_warn(&pdev->dev,
			 "This platform can't do DMA on this device\n");
	}

	ret = pxa3xx_nand_probe_dt(pdev);
	if (ret)
		return ret;

	pdata = dev_get_platdata(&pdev->dev);
	if (!pdata) {
		dev_err(&pdev->dev, "no platform data defined\n");
		return -ENODEV;
	}

	ret = alloc_nand_resource(pdev);
	if (ret)
		return ret;

	info = platform_get_drvdata(pdev);
	probe_success = 0;
	for (cs = 0; cs < pdata->num_cs; cs++) {
		struct mtd_info *mtd = nand_to_mtd(&info->host[cs]->chip);

		/*
		 * The mtd name matches the one used in 'mtdparts' kernel
		 * parameter. This name cannot be changed or otherwise
		 * user's mtd partitions configuration would get broken.
		 */
		mtd->name = "pxa3xx_nand-0";
		info->cs = cs;
		ret = pxa3xx_nand_scan(mtd);
		if (ret) {
			dev_warn(&pdev->dev, "failed to scan nand at cs %d\n",
				cs);
			continue;
		}

		ret = mtd_device_register(mtd, pdata->parts[cs],
					  pdata->nr_parts[cs]);
		if (!ret)
			probe_success = 1;
	}

	if (!probe_success) {
		pxa3xx_nand_remove(pdev);
		return -ENODEV;
	}

	return 0;
}

#ifdef CONFIG_PM
static int pxa3xx_nand_suspend(struct device *dev)
{
	struct pxa3xx_nand_info *info = dev_get_drvdata(dev);

	if (info->state) {
		dev_err(dev, "driver busy, state = %d\n", info->state);
		return -EAGAIN;
	}

	clk_disable(info->clk);
	return 0;
}

static int pxa3xx_nand_resume(struct device *dev)
{
	struct pxa3xx_nand_info *info = dev_get_drvdata(dev);
	int ret;

	ret = clk_enable(info->clk);
	if (ret < 0)
		return ret;

	/* We don't want to handle interrupt without calling mtd routine */
	disable_int(info, NDCR_INT_MASK);

	/*
	 * Directly set the chip select to a invalid value,
	 * then the driver would reset the timing according
	 * to current chip select at the beginning of cmdfunc
	 */
	info->cs = 0xff;

	/*
	 * As the spec says, the NDSR would be updated to 0x1800 when
	 * doing the nand_clk disable/enable.
	 * To prevent it damaging state machine of the driver, clear
	 * all status before resume
	 */
	nand_writel(info, NDSR, NDSR_MASK);

	return 0;
}
#else
#define pxa3xx_nand_suspend	NULL
#define pxa3xx_nand_resume	NULL
#endif

static const struct dev_pm_ops pxa3xx_nand_pm_ops = {
	.suspend	= pxa3xx_nand_suspend,
	.resume		= pxa3xx_nand_resume,
};

static struct platform_driver pxa3xx_nand_driver = {
	.driver = {
		.name	= "pxa3xx-nand",
		.of_match_table = pxa3xx_nand_dt_ids,
		.pm	= &pxa3xx_nand_pm_ops,
	},
	.probe		= pxa3xx_nand_probe,
	.remove		= pxa3xx_nand_remove,
};

module_platform_driver(pxa3xx_nand_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("PXA3xx NAND controller driver");