[deliverable/linux.git] / 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.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.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/irq.h>
#include <linux/slab.h>

#include <mach/dma.h>
#include <plat/pxa3xx_nand.h>

#define	CHIP_DELAY_TIMEOUT	(2 * HZ/10)
#define NAND_STOP_DELAY		(2 * HZ/50)
#define PAGE_CHUNK_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 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 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_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_DBERR		(0x1 << 4)
#define NDSR_SBERR		(0x1 << 3)
#define NDSR_WRDREQ		(0x1 << 2)
#define NDSR_RDDREQ		(0x1 << 1)
#define NDSR_WRCMDREQ		(0x1)

#define NDCB0_ST_ROW_EN         (0x1 << 26)
#define NDCB0_AUTO_RS		(0x1 << 25)
#define NDCB0_CSEL		(0x1 << 24)
#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)

/* macros for registers read/write */
#define nand_writel(info, off, val)	\
	__raw_writel((val), (info)->mmio_base + (off))

#define nand_readl(info, off)		\
	__raw_readl((info)->mmio_base + (off))

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

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

struct pxa3xx_nand_info {
	struct nand_chip	nand_chip;

	struct nand_hw_control	controller;
	struct platform_device	 *pdev;
	struct pxa3xx_nand_cmdset *cmdset;

	struct clk		*clk;
	void __iomem		*mmio_base;
	unsigned long		mmio_phys;

	unsigned int 		buf_start;
	unsigned int		buf_count;

	struct mtd_info         *mtd;
	/* DMA information */
	int			drcmr_dat;
	int			drcmr_cmd;

	unsigned char		*data_buff;
	unsigned char		*oob_buff;
	dma_addr_t 		data_buff_phys;
	size_t			data_buff_size;
	int 			data_dma_ch;
	struct pxa_dma_desc	*data_desc;
	dma_addr_t 		data_desc_addr;

	uint32_t		reg_ndcr;

	/* saved column/page_addr during CMD_SEQIN */
	int			seqin_column;
	int			seqin_page_addr;

	/* relate to the command */
	unsigned int		state;

	int			use_ecc;	/* use HW ECC ? */
	int			use_dma;	/* use DMA ? */
	int			is_ready;

	unsigned int		page_size;	/* page size of attached chip */
	unsigned int		data_size;	/* data size in FIFO */
	int 			retcode;
	struct completion 	cmd_complete;

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

	/* timing calcuted from setting */
	uint32_t		ndtr0cs0;
	uint32_t		ndtr1cs0;

	/* calculated from pxa3xx_nand_flash data */
	size_t		oob_size;
	size_t		read_id_bytes;

	unsigned int	col_addr_cycles;
	unsigned int	row_addr_cycles;
};

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

/*
 * Default NAND flash controller configuration setup by the
 * bootloader. This configuration is used only when pdata->keep_config is set
 */
static struct pxa3xx_nand_cmdset default_cmdset = {
	.read1		= 0x3000,
	.read2		= 0x0050,
	.program	= 0x1080,
	.read_status	= 0x0070,
	.read_id	= 0x0090,
	.erase		= 0xD060,
	.reset		= 0x00FF,
	.lock		= 0x002A,
	.unlock		= 0x2423,
	.lock_status	= 0x007A,
};

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[] = {
{ "DEFAULT FLASH",      0,   0, 2048,  8,  8,    0, &timing[0] },
{ "64MiB 16-bit",  0x46ec,  32,  512, 16, 16, 4096, &timing[1] },
{ "256MiB 8-bit",  0xdaec,  64, 2048,  8,  8, 2048, &timing[1] },
{ "4GiB 8-bit",    0xd7ec, 128, 4096,  8,  8, 8192, &timing[1] },
{ "128MiB 8-bit",  0xa12c,  64, 2048,  8,  8, 1024, &timing[2] },
{ "128MiB 16-bit", 0xb12c,  64, 2048, 16, 16, 1024, &timing[2] },
{ "512MiB 8-bit",  0xdc2c,  64, 2048,  8,  8, 4096, &timing[2] },
{ "512MiB 16-bit", 0xcc2c,  64, 2048, 16, 16, 4096, &timing[2] },
{ "256MiB 16-bit", 0xba20,  64, 2048, 16, 16, 2048, &timing[3] },
};

/* Define a default flash type setting serve as flash detecting only */
#define DEFAULT_FLASH_TYPE (&builtin_flash_types[0])

const char *mtd_names[] = {"pxa3xx_nand-0", NULL};

#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 void pxa3xx_nand_set_timing(struct pxa3xx_nand_info *info,
				   const struct pxa3xx_nand_timing *t)
{
	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_set_datasize(struct pxa3xx_nand_info *info)
{
	int oob_enable = info->reg_ndcr & NDCR_SPARE_EN;

	info->data_size = info->page_size;
	if (!oob_enable) {
		info->oob_size = 0;
		return;
	}

	switch (info->page_size) {
	case 2048:
		info->oob_size = (info->use_ecc) ? 40 : 64;
		break;
	case 512:
		info->oob_size = (info->use_ecc) ? 8 : 16;
		break;
	}
}

/**
 * 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;
	ndcr |= info->use_ecc ? NDCR_ECC_EN : 0;
	ndcr |= info->use_dma ? NDCR_DMA_EN : 0;
	ndcr |= NDCR_ND_RUN;

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

static void 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 handle_data_pio(struct pxa3xx_nand_info *info)
{
	switch (info->state) {
	case STATE_PIO_WRITING:
		__raw_writesl(info->mmio_base + NDDB, info->data_buff,
				DIV_ROUND_UP(info->data_size, 4));
		if (info->oob_size > 0)
			__raw_writesl(info->mmio_base + NDDB, info->oob_buff,
					DIV_ROUND_UP(info->oob_size, 4));
		break;
	case STATE_PIO_READING:
		__raw_readsl(info->mmio_base + NDDB, info->data_buff,
				DIV_ROUND_UP(info->data_size, 4));
		if (info->oob_size > 0)
			__raw_readsl(info->mmio_base + NDDB, info->oob_buff,
					DIV_ROUND_UP(info->oob_size, 4));
		break;
	default:
		printk(KERN_ERR "%s: invalid state %d\n", __func__,
				info->state);
		BUG();
	}
}

static void start_data_dma(struct pxa3xx_nand_info *info)
{
	struct pxa_dma_desc *desc = info->data_desc;
	int dma_len = ALIGN(info->data_size + info->oob_size, 32);

	desc->ddadr = DDADR_STOP;
	desc->dcmd = DCMD_ENDIRQEN | DCMD_WIDTH4 | DCMD_BURST32 | dma_len;

	switch (info->state) {
	case STATE_DMA_WRITING:
		desc->dsadr = info->data_buff_phys;
		desc->dtadr = info->mmio_phys + NDDB;
		desc->dcmd |= DCMD_INCSRCADDR | DCMD_FLOWTRG;
		break;
	case STATE_DMA_READING:
		desc->dtadr = info->data_buff_phys;
		desc->dsadr = info->mmio_phys + NDDB;
		desc->dcmd |= DCMD_INCTRGADDR | DCMD_FLOWSRC;
		break;
	default:
		printk(KERN_ERR "%s: invalid state %d\n", __func__,
				info->state);
		BUG();
	}

	DRCMR(info->drcmr_dat) = DRCMR_MAPVLD | info->data_dma_ch;
	DDADR(info->data_dma_ch) = info->data_desc_addr;
	DCSR(info->data_dma_ch) |= DCSR_RUN;
}

static void pxa3xx_nand_data_dma_irq(int channel, void *data)
{
	struct pxa3xx_nand_info *info = data;
	uint32_t dcsr;

	dcsr = DCSR(channel);
	DCSR(channel) = dcsr;

	if (dcsr & DCSR_BUSERR) {
		info->retcode = ERR_DMABUSERR;
	}

	info->state = STATE_DMA_DONE;
	enable_int(info, NDCR_INT_MASK);
	nand_writel(info, NDSR, NDSR_WRDREQ | NDSR_RDDREQ);
}

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

	status = nand_readl(info, NDSR);

	if (status & NDSR_DBERR)
		info->retcode = ERR_DBERR;
	if (status & NDSR_SBERR)
		info->retcode = ERR_SBERR;
	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;
			handle_data_pio(info);
		}
	}
	if (status & NDSR_CS0_CMDD) {
		info->state = STATE_CMD_DONE;
		is_completed = 1;
	}
	if (status & NDSR_FLASH_RDY) {
		info->is_ready = 1;
		info->state = STATE_READY;
	}

	if (status & NDSR_WRCMDREQ) {
		nand_writel(info, NDSR, NDSR_WRCMDREQ);
		status &= ~NDSR_WRCMDREQ;
		info->state = STATE_CMD_HANDLE;
		nand_writel(info, NDCB0, info->ndcb0);
		nand_writel(info, NDCB0, info->ndcb1);
		nand_writel(info, NDCB0, info->ndcb2);
	}

	/* clear NDSR to let the controller exit the IRQ */
	nand_writel(info, NDSR, status);
	if (is_completed)
		complete(&info->cmd_complete);
NORMAL_IRQ_EXIT:
	return IRQ_HANDLED;
}

static int pxa3xx_nand_dev_ready(struct mtd_info *mtd)
{
	struct pxa3xx_nand_info *info = mtd->priv;
	return (nand_readl(info, NDSR) & NDSR_RDY) ? 1 : 0;
}

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

static int prepare_command_pool(struct pxa3xx_nand_info *info, int command,
		uint16_t column, int page_addr)
{
	uint16_t cmd;
	int addr_cycle, exec_cmd, ndcb0;
	struct mtd_info *mtd = info->mtd;

	ndcb0 = 0;
	addr_cycle = 0;
	exec_cmd = 1;

	/* reset data and oob column point to handle data */
	info->buf_start		= 0;
	info->buf_count		= 0;
	info->oob_size		= 0;
	info->use_ecc		= 0;
	info->is_ready		= 0;
	info->retcode		= ERR_NONE;

	switch (command) {
	case NAND_CMD_READ0:
	case NAND_CMD_PAGEPROG:
		info->use_ecc = 1;
	case NAND_CMD_READOOB:
		pxa3xx_set_datasize(info);
		break;
	case NAND_CMD_SEQIN:
		exec_cmd = 0;
		break;
	default:
		info->ndcb1 = 0;
		info->ndcb2 = 0;
		break;
	}

	info->ndcb0 = ndcb0;
	addr_cycle = NDCB0_ADDR_CYC(info->row_addr_cycles
				    + info->col_addr_cycles);

	switch (command) {
	case NAND_CMD_READOOB:
	case NAND_CMD_READ0:
		cmd = info->cmdset->read1;
		if (command == NAND_CMD_READOOB)
			info->buf_start = mtd->writesize + column;
		else
			info->buf_start = column;

		if (unlikely(info->page_size < PAGE_CHUNK_SIZE))
			info->ndcb0 |= NDCB0_CMD_TYPE(0)
					| addr_cycle
					| (cmd & NDCB0_CMD1_MASK);
		else
			info->ndcb0 |= NDCB0_CMD_TYPE(0)
					| NDCB0_DBC
					| addr_cycle
					| cmd;

	case NAND_CMD_SEQIN:
		/* small page addr setting */
		if (unlikely(info->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;
		}

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

		break;

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

		cmd = info->cmdset->program;
		info->ndcb0 |= NDCB0_CMD_TYPE(0x1)
				| NDCB0_AUTO_RS
				| NDCB0_ST_ROW_EN
				| NDCB0_DBC
				| cmd
				| addr_cycle;
		break;

	case NAND_CMD_READID:
		cmd = info->cmdset->read_id;
		info->buf_count = info->read_id_bytes;
		info->ndcb0 |= NDCB0_CMD_TYPE(3)
				| NDCB0_ADDR_CYC(1)
				| cmd;

		info->data_size = 8;
		break;
	case NAND_CMD_STATUS:
		cmd = info->cmdset->read_status;
		info->buf_count = 1;
		info->ndcb0 |= NDCB0_CMD_TYPE(4)
				| NDCB0_ADDR_CYC(1)
				| cmd;

		info->data_size = 8;
		break;

	case NAND_CMD_ERASE1:
		cmd = info->cmdset->erase;
		info->ndcb0 |= NDCB0_CMD_TYPE(2)
				| NDCB0_AUTO_RS
				| NDCB0_ADDR_CYC(3)
				| NDCB0_DBC
				| cmd;
		info->ndcb1 = page_addr;
		info->ndcb2 = 0;

		break;
	case NAND_CMD_RESET:
		cmd = info->cmdset->reset;
		info->ndcb0 |= NDCB0_CMD_TYPE(5)
				| cmd;

		break;

	case NAND_CMD_ERASE2:
		exec_cmd = 0;
		break;

	default:
		exec_cmd = 0;
		printk(KERN_ERR "pxa3xx-nand: non-supported"
			" command %x\n", command);
		break;
	}

	return exec_cmd;
}

static void pxa3xx_nand_cmdfunc(struct mtd_info *mtd, unsigned command,
				int column, int page_addr)
{
	struct pxa3xx_nand_info *info = mtd->priv;
	int ret, 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;

	exec_cmd = prepare_command_pool(info, command, column, page_addr);
	if (exec_cmd) {
		init_completion(&info->cmd_complete);
		pxa3xx_nand_start(info);

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

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

static int pxa3xx_nand_read_page_hwecc(struct mtd_info *mtd,
		struct nand_chip *chip, uint8_t *buf, int page)
{
	struct pxa3xx_nand_info *info = mtd->priv;

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

	if (info->retcode == ERR_SBERR) {
		switch (info->use_ecc) {
		case 1:
			mtd->ecc_stats.corrected++;
			break;
		case 0:
		default:
			break;
		}
	} else if (info->retcode == ERR_DBERR) {
		/*
		 * for blank page (all 0xff), HW will calculate its ECC as
		 * 0, which is different from the ECC information within
		 * OOB, ignore such double bit errors
		 */
		if (is_buf_blank(buf, mtd->writesize))
			info->retcode = ERR_NONE;
		else
			mtd->ecc_stats.failed++;
	}

	return 0;
}

static uint8_t pxa3xx_nand_read_byte(struct mtd_info *mtd)
{
	struct pxa3xx_nand_info *info = mtd->priv;
	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 pxa3xx_nand_info *info = mtd->priv;
	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 pxa3xx_nand_info *info = mtd->priv;
	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 pxa3xx_nand_info *info = mtd->priv;
	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 int pxa3xx_nand_verify_buf(struct mtd_info *mtd,
		const uint8_t *buf, int len)
{
	return 0;
}

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 pxa3xx_nand_info *info = mtd->priv;

	/* 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 {
			/*
			 * any error make it return 0x01 which will tell
			 * the caller the erase and write fail
			 */
			return 0x01;
		}
	}

	return 0;
}

static int pxa3xx_nand_config_flash(struct pxa3xx_nand_info *info,
				    const struct pxa3xx_nand_flash *f)
{
	struct platform_device *pdev = info->pdev;
	struct pxa3xx_nand_platform_data *pdata = pdev->dev.platform_data;
	uint32_t ndcr = 0x0; /* enable all interrupts */

	if (f->page_size != 2048 && f->page_size != 512)
		return -EINVAL;

	if (f->flash_width != 16 && f->flash_width != 8)
		return -EINVAL;

	/* calculate flash information */
	info->cmdset = &default_cmdset;
	info->page_size = f->page_size;
	info->read_id_bytes = (f->page_size == 2048) ? 4 : 2;

	/* calculate addressing information */
	info->col_addr_cycles = (f->page_size == 2048) ? 2 : 1;

	if (f->num_blocks * f->page_per_block > 65536)
		info->row_addr_cycles = 3;
	else
		info->row_addr_cycles = 2;

	ndcr |= (pdata->enable_arbiter) ? NDCR_ND_ARB_EN : 0;
	ndcr |= (info->col_addr_cycles == 2) ? NDCR_RA_START : 0;
	ndcr |= (f->page_per_block == 64) ? NDCR_PG_PER_BLK : 0;
	ndcr |= (f->page_size == 2048) ? NDCR_PAGE_SZ : 0;
	ndcr |= (f->flash_width == 16) ? NDCR_DWIDTH_M : 0;
	ndcr |= (f->dfc_width == 16) ? NDCR_DWIDTH_C : 0;

	ndcr |= NDCR_RD_ID_CNT(info->read_id_bytes);
	ndcr |= NDCR_SPARE_EN; /* enable spare by default */

	info->reg_ndcr = ndcr;

	pxa3xx_nand_set_timing(info, f->timing);
	return 0;
}

static int pxa3xx_nand_detect_config(struct pxa3xx_nand_info *info)
{
	uint32_t ndcr = nand_readl(info, NDCR);
	info->page_size = ndcr & NDCR_PAGE_SZ ? 2048 : 512;
	/* set info fields needed to read id */
	info->read_id_bytes = (info->page_size == 2048) ? 4 : 2;
	info->reg_ndcr = ndcr & ~NDCR_INT_MASK;
	info->cmdset = &default_cmdset;

	info->ndtr0cs0 = nand_readl(info, NDTR0CS0);
	info->ndtr1cs0 = nand_readl(info, NDTR1CS0);

	return 0;
}

/* the maximum possible buffer size for large page with OOB data
 * is: 2048 + 64 = 2112 bytes, allocate a page here for both the
 * data buffer and the DMA descriptor
 */
#define MAX_BUFF_SIZE	PAGE_SIZE

static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
{
	struct platform_device *pdev = info->pdev;
	int data_desc_offset = MAX_BUFF_SIZE - sizeof(struct pxa_dma_desc);

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

	info->data_buff = dma_alloc_coherent(&pdev->dev, MAX_BUFF_SIZE,
				&info->data_buff_phys, GFP_KERNEL);
	if (info->data_buff == NULL) {
		dev_err(&pdev->dev, "failed to allocate dma buffer\n");
		return -ENOMEM;
	}

	info->data_buff_size = MAX_BUFF_SIZE;
	info->data_desc = (void *)info->data_buff + data_desc_offset;
	info->data_desc_addr = info->data_buff_phys + data_desc_offset;

	info->data_dma_ch = pxa_request_dma("nand-data", DMA_PRIO_LOW,
				pxa3xx_nand_data_dma_irq, info);
	if (info->data_dma_ch < 0) {
		dev_err(&pdev->dev, "failed to request data dma\n");
		dma_free_coherent(&pdev->dev, info->data_buff_size,
				info->data_buff, info->data_buff_phys);
		return info->data_dma_ch;
	}

	return 0;
}

static int pxa3xx_nand_sensing(struct pxa3xx_nand_info *info)
{
	struct mtd_info *mtd = info->mtd;
	struct nand_chip *chip = mtd->priv;

	/* use the common timing to make a try */
	pxa3xx_nand_config_flash(info, &builtin_flash_types[0]);
	chip->cmdfunc(mtd, NAND_CMD_RESET, 0, 0);
	if (info->is_ready)
		return 1;
	else
		return 0;
}

static int pxa3xx_nand_scan(struct mtd_info *mtd)
{
	struct pxa3xx_nand_info *info = mtd->priv;
	struct platform_device *pdev = info->pdev;
	struct pxa3xx_nand_platform_data *pdata = pdev->dev.platform_data;
	struct nand_flash_dev pxa3xx_flash_ids[2], *def = NULL;
	const struct pxa3xx_nand_flash *f = NULL;
	struct nand_chip *chip = mtd->priv;
	uint32_t id = -1;
	uint64_t chipsize;
	int i, ret, num;

	if (pdata->keep_config && !pxa3xx_nand_detect_config(info))
		goto KEEP_CONFIG;

	ret = pxa3xx_nand_sensing(info);
	if (!ret) {
		kfree(mtd);
		info->mtd = NULL;
		printk(KERN_INFO "There is no nand chip on cs 0!\n");

		return -EINVAL;
	}

	chip->cmdfunc(mtd, NAND_CMD_READID, 0, 0);
	id = *((uint16_t *)(info->data_buff));
	if (id != 0)
		printk(KERN_INFO "Detect a flash id %x\n", id);
	else {
		kfree(mtd);
		info->mtd = NULL;
		printk(KERN_WARNING "Read out ID 0, potential timing set wrong!!\n");

		return -EINVAL;
	}

	num = ARRAY_SIZE(builtin_flash_types) + pdata->num_flash - 1;
	for (i = 0; i < num; i++) {
		if (i < pdata->num_flash)
			f = pdata->flash + i;
		else
			f = &builtin_flash_types[i - pdata->num_flash + 1];

		/* find the chip in default list */
		if (f->chip_id == id)
			break;
	}

	if (i >= (ARRAY_SIZE(builtin_flash_types) + pdata->num_flash - 1)) {
		kfree(mtd);
		info->mtd = NULL;
		printk(KERN_ERR "ERROR!! flash not defined!!!\n");

		return -EINVAL;
	}

	pxa3xx_nand_config_flash(info, f);
	pxa3xx_flash_ids[0].name = f->name;
	pxa3xx_flash_ids[0].id = (f->chip_id >> 8) & 0xffff;
	pxa3xx_flash_ids[0].pagesize = f->page_size;
	chipsize = (uint64_t)f->num_blocks * f->page_per_block * f->page_size;
	pxa3xx_flash_ids[0].chipsize = chipsize >> 20;
	pxa3xx_flash_ids[0].erasesize = f->page_size * f->page_per_block;
	if (f->flash_width == 16)
		pxa3xx_flash_ids[0].options = NAND_BUSWIDTH_16;
	pxa3xx_flash_ids[1].name = NULL;
	def = pxa3xx_flash_ids;
KEEP_CONFIG:
	if (nand_scan_ident(mtd, 1, def))
		return -ENODEV;
	/* calculate addressing information */
	info->col_addr_cycles = (mtd->writesize >= 2048) ? 2 : 1;
	info->oob_buff = info->data_buff + mtd->writesize;
	if ((mtd->size >> chip->page_shift) > 65536)
		info->row_addr_cycles = 3;
	else
		info->row_addr_cycles = 2;
	mtd->name = mtd_names[0];
	chip->ecc.mode = NAND_ECC_HW;
	chip->ecc.size = info->page_size;

	chip->options = (info->reg_ndcr & NDCR_DWIDTH_M) ? NAND_BUSWIDTH_16 : 0;
	chip->options |= NAND_NO_AUTOINCR;
	chip->options |= NAND_NO_READRDY;

	return nand_scan_tail(mtd);
}

static
struct pxa3xx_nand_info *alloc_nand_resource(struct platform_device *pdev)
{
	struct pxa3xx_nand_info *info;
	struct nand_chip *chip;
	struct mtd_info *mtd;
	struct resource *r;
	int ret, irq;

	mtd = kzalloc(sizeof(struct mtd_info) + sizeof(struct pxa3xx_nand_info),
			GFP_KERNEL);
	if (!mtd) {
		dev_err(&pdev->dev, "failed to allocate memory\n");
		return NULL;
	}

	info = (struct pxa3xx_nand_info *)(&mtd[1]);
	chip = (struct nand_chip *)(&mtd[1]);
	info->pdev = pdev;
	info->mtd = mtd;
	mtd->priv = info;
	mtd->owner = THIS_MODULE;

	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->dev_ready		= pxa3xx_nand_dev_ready;
	chip->cmdfunc		= pxa3xx_nand_cmdfunc;
	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->verify_buf	= pxa3xx_nand_verify_buf;

	spin_lock_init(&chip->controller->lock);
	init_waitqueue_head(&chip->controller->wq);
	info->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(info->clk)) {
		dev_err(&pdev->dev, "failed to get nand clock\n");
		ret = PTR_ERR(info->clk);
		goto fail_free_mtd;
	}
	clk_enable(info->clk);

	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_put_clk;
	}
	info->drcmr_dat = r->start;

	r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
	if (r == NULL) {
		dev_err(&pdev->dev, "no resource defined for command DMA\n");
		ret = -ENXIO;
		goto fail_put_clk;
	}
	info->drcmr_cmd = r->start;

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

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (r == NULL) {
		dev_err(&pdev->dev, "no IO memory resource defined\n");
		ret = -ENODEV;
		goto fail_put_clk;
	}

	r = request_mem_region(r->start, resource_size(r), pdev->name);
	if (r == NULL) {
		dev_err(&pdev->dev, "failed to request memory resource\n");
		ret = -EBUSY;
		goto fail_put_clk;
	}

	info->mmio_base = ioremap(r->start, resource_size(r));
	if (info->mmio_base == NULL) {
		dev_err(&pdev->dev, "ioremap() failed\n");
		ret = -ENODEV;
		goto fail_free_res;
	}
	info->mmio_phys = r->start;

	ret = pxa3xx_nand_init_buff(info);
	if (ret)
		goto fail_free_io;

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

	ret = request_irq(irq, pxa3xx_nand_irq, IRQF_DISABLED,
			  pdev->name, info);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to request IRQ\n");
		goto fail_free_buf;
	}

	platform_set_drvdata(pdev, info);

	return info;

fail_free_buf:
	free_irq(irq, info);
	if (use_dma) {
		pxa_free_dma(info->data_dma_ch);
		dma_free_coherent(&pdev->dev, info->data_buff_size,
			info->data_buff, info->data_buff_phys);
	} else
		kfree(info->data_buff);
fail_free_io:
	iounmap(info->mmio_base);
fail_free_res:
	release_mem_region(r->start, resource_size(r));
fail_put_clk:
	clk_disable(info->clk);
	clk_put(info->clk);
fail_free_mtd:
	kfree(mtd);
	return NULL;
}

static int pxa3xx_nand_remove(struct platform_device *pdev)
{
	struct pxa3xx_nand_info *info = platform_get_drvdata(pdev);
	struct mtd_info *mtd = info->mtd;
	struct resource *r;
	int irq;

	platform_set_drvdata(pdev, NULL);

	irq = platform_get_irq(pdev, 0);
	if (irq >= 0)
		free_irq(irq, info);
	if (use_dma) {
		pxa_free_dma(info->data_dma_ch);
		dma_free_writecombine(&pdev->dev, info->data_buff_size,
				info->data_buff, info->data_buff_phys);
	} else
		kfree(info->data_buff);

	iounmap(info->mmio_base);
	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(r->start, resource_size(r));

	clk_disable(info->clk);
	clk_put(info->clk);

	if (mtd) {
		nand_release(mtd);
		kfree(mtd);
	}
	return 0;
}

static int pxa3xx_nand_probe(struct platform_device *pdev)
{
	struct pxa3xx_nand_platform_data *pdata;
	struct pxa3xx_nand_info *info;

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

	info = alloc_nand_resource(pdev);
	if (info == NULL)
		return -ENOMEM;

	if (pxa3xx_nand_scan(info->mtd)) {
		dev_err(&pdev->dev, "failed to scan nand\n");
		pxa3xx_nand_remove(pdev);
		return -ENODEV;
	}

	return mtd_device_parse_register(info->mtd, NULL, 0,
			pdata->parts, pdata->nr_parts);
}

#ifdef CONFIG_PM
static int pxa3xx_nand_suspend(struct platform_device *pdev, pm_message_t state)
{
	struct pxa3xx_nand_info *info = platform_get_drvdata(pdev);

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

	return 0;
}

static int pxa3xx_nand_resume(struct platform_device *pdev)
{
	struct pxa3xx_nand_info *info = platform_get_drvdata(pdev);

	nand_writel(info, NDTR0CS0, info->ndtr0cs0);
	nand_writel(info, NDTR1CS0, info->ndtr1cs0);
	clk_enable(info->clk);

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

static struct platform_driver pxa3xx_nand_driver = {
	.driver = {
		.name	= "pxa3xx-nand",
	},
	.probe		= pxa3xx_nand_probe,
	.remove		= pxa3xx_nand_remove,
	.suspend	= pxa3xx_nand_suspend,
	.resume		= pxa3xx_nand_resume,
};

static int __init pxa3xx_nand_init(void)
{
	return platform_driver_register(&pxa3xx_nand_driver);
}
module_init(pxa3xx_nand_init);

static void __exit pxa3xx_nand_exit(void)
{
	platform_driver_unregister(&pxa3xx_nand_driver);
}
module_exit(pxa3xx_nand_exit);

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