/*
 * 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/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 <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_mtd.h>

#if defined(CONFIG_ARCH_PXA) || defined(CONFIG_ARCH_MMP)
#define ARCH_HAS_DMA
#endif

#ifdef ARCH_HAS_DMA
#include <mach/dma.h>
#endif

#include <linux/platform_data/mtd-nand-pxa3xx.h>

#define CHIP_DELAY_TIMEOUT      (2 * HZ/10)
#define NAND_STOP_DELAY         (2 * HZ/50)
#define PAGE_CHUNK_SIZE         (2048)

/*
 * Define a buffer size for the initial command that detects the flash device:
 * STATUS, READID and PARAM. The largest of these is the PARAM command,
 * needing 256 bytes.
 */
#define INIT_BUFFER_SIZE        256

/* 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 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 */

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

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

/* 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;
        struct mtd_info         *mtd;
        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;
        size_t                  read_id_bytes;

};

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 */
        int                     drcmr_dat;
        int                     drcmr_cmd;

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

        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;

        unsigned int            data_size;      /* data to be read from FIFO */
        unsigned int            chunk_size;     /* split commands chunk size */
        unsigned int            oob_size;
        unsigned int            spare_size;
        unsigned int            ecc_size;
        unsigned int            ecc_err_cnt;
        unsigned int            max_bitflips;
        int                     retcode;

        /* 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");

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] },
};

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
};

static struct nand_ecclayout ecc_layout_2KB_bch4bit = {
        .eccbytes = 32,
        .eccpos = {
                32, 33, 34, 35, 36, 37, 38, 39,
                40, 41, 42, 43, 44, 45, 46, 47,
                48, 49, 50, 51, 52, 53, 54, 55,
                56, 57, 58, 59, 60, 61, 62, 63},
        .oobfree = { {2, 30} }
};

static struct nand_ecclayout ecc_layout_4KB_bch4bit = {
        .eccbytes = 64,
        .eccpos = {
                32,  33,  34,  35,  36,  37,  38,  39,
                40,  41,  42,  43,  44,  45,  46,  47,
                48,  49,  50,  51,  52,  53,  54,  55,
                56,  57,  58,  59,  60,  61,  62,  63,
                96,  97,  98,  99,  100, 101, 102, 103,
                104, 105, 106, 107, 108, 109, 110, 111,
                112, 113, 114, 115, 116, 117, 118, 119,
                120, 121, 122, 123, 124, 125, 126, 127},
        /* Bootrom looks in bytes 0 & 5 for bad blocks */
        .oobfree = { {6, 26}, { 64, 32} }
};

static struct nand_ecclayout ecc_layout_4KB_bch8bit = {
        .eccbytes = 128,
        .eccpos = {
                32,  33,  34,  35,  36,  37,  38,  39,
                40,  41,  42,  43,  44,  45,  46,  47,
                48,  49,  50,  51,  52,  53,  54,  55,
                56,  57,  58,  59,  60,  61,  62,  63},
        .oobfree = { }
};

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

#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);
}

/*
 * Set the data and OOB size, depending on the selected
 * spare and ECC configuration.
 * Only applicable to READ0, READOOB and PAGEPROG commands.
 */
static void pxa3xx_set_datasize(struct pxa3xx_nand_info *info,
                                struct mtd_info *mtd)
{
        int oob_enable = info->reg_ndcr & NDCR_SPARE_EN;

        info->data_size = mtd->writesize;
        if (!oob_enable)
                return;

        info->oob_size = info->spare_size;
        if (!info->use_ecc)
                info->oob_size += info->ecc_size;
}

/**
 * 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, 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 __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 handle_data_pio(struct pxa3xx_nand_info *info)
{
        unsigned int do_bytes = min(info->data_size, info->chunk_size);

        switch (info->state) {
        case STATE_PIO_WRITING:
                __raw_writesl(info->mmio_base + NDDB,
                              info->data_buff + info->data_buff_pos,
                              DIV_ROUND_UP(do_bytes, 4));

                if (info->oob_size > 0)
                        __raw_writesl(info->mmio_base + NDDB,
                                      info->oob_buff + info->oob_buff_pos,
                                      DIV_ROUND_UP(info->oob_size, 4));
                break;
        case STATE_PIO_READING:
                __raw_readsl(info->mmio_base + NDDB,
                             info->data_buff + info->data_buff_pos,
                             DIV_ROUND_UP(do_bytes, 4));

                if (info->oob_size > 0)
                        __raw_readsl(info->mmio_base + NDDB,
                                     info->oob_buff + info->oob_buff_pos,
                                     DIV_ROUND_UP(info->oob_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 += do_bytes;
        info->oob_buff_pos += info->oob_size;
        info->data_size -= do_bytes;
}

#ifdef ARCH_HAS_DMA
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:
                dev_err(&info->pdev->dev, "%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);
}
#else
static void start_data_dma(struct pxa3xx_nand_info *info)
{}
#endif

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;

        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;
                        handle_data_pio(info);
                }
        }
        if (status & cmd_done) {
                info->state = STATE_CMD_DONE;
                is_completed = 1;
        }
        if (status & ready) {
                info->state = STATE_READY;
                is_ready = 1;
        }

        if (status & NDSR_WRCMDREQ) {
                nand_writel(info, NDSR, 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);
        }

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

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 = host->mtd;

        /* reset data and oob column point to handle data */
        info->buf_start         = 0;
        info->buf_count         = 0;
        info->oob_size          = 0;
        info->data_buff_pos     = 0;
        info->oob_buff_pos      = 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;
        case NAND_CMD_READOOB:
                pxa3xx_set_datasize(info, mtd);
                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 = host->mtd;
        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;

                /*
                 * 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->chunk_size +
                                      info->oob_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;
                        /* No data transfer in this case */
                        info->data_size = 0;
                        exec_cmd = 1;
                }
                break;

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

                /* 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->chunk_size +
                                      info->oob_size;

                        /*
                         * This is the command dispatch that completes a chunked
                         * page program operation.
                         */
                        if (info->data_size == 0) {
                                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 = 256;
                info->ndcb0 |= NDCB0_CMD_TYPE(0)
                                | NDCB0_ADDR_CYC(1)
                                | NDCB0_LEN_OVRD
                                | command;
                info->ndcb1 = (column & 0xFF);
                info->ndcb3 = 256;
                info->data_size = 256;
                break;

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

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

                info->data_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 pxa3xx_nand_host *host = mtd->priv;
        struct pxa3xx_nand_info *info = host->info_data;
        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;

        /*
         * 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);

                ret = wait_for_completion_timeout(&info->cmd_complete,
                                CHIP_DELAY_TIMEOUT);
                if (!ret) {
                        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 pxa3xx_nand_host *host = mtd->priv;
        struct pxa3xx_nand_info *info = host->info_data;
        int ret, 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);

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

                /* Check if the sequence is complete */
                if (info->data_size == 0 && command != NAND_CMD_PAGEPROG)
                        break;

                /*
                 * After a splitted program command sequence has issued
                 * the command dispatch, the command sequence is complete.
                 */
                if (info->data_size == 0 &&
                    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->data_size == info->chunk_size)
                                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->data_size == 0) {
                                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)
{
        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 = mtd->priv;
        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 pxa3xx_nand_host *host = mtd->priv;
        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 pxa3xx_nand_host *host = mtd->priv;
        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 pxa3xx_nand_host *host = mtd->priv;
        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 pxa3xx_nand_host *host = mtd->priv;
        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 pxa3xx_nand_host *host = mtd->priv;
        struct pxa3xx_nand_info *info = host->info_data;
        int ret;

        if (info->need_wait) {
                ret = wait_for_completion_timeout(&info->dev_ready,
                                CHIP_DELAY_TIMEOUT);
                info->need_wait = 0;
                if (!ret) {
                        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_flash(struct pxa3xx_nand_info *info,
                                    const struct pxa3xx_nand_flash *f)
{
        struct platform_device *pdev = info->pdev;
        struct pxa3xx_nand_platform_data *pdata = dev_get_platdata(&pdev->dev);
        struct pxa3xx_nand_host *host = info->host[info->cs];
        uint32_t ndcr = 0x0; /* enable all interrupts */

        if (f->page_size != 2048 && f->page_size != 512) {
                dev_err(&pdev->dev, "Current only support 2048 and 512 size\n");
                return -EINVAL;
        }

        if (f->flash_width != 16 && f->flash_width != 8) {
                dev_err(&pdev->dev, "Only support 8bit and 16 bit!\n");
                return -EINVAL;
        }

        /* calculate flash information */
        host->read_id_bytes = (f->page_size == 2048) ? 4 : 2;

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

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

        ndcr |= (pdata->enable_arbiter) ? NDCR_ND_ARB_EN : 0;
        ndcr |= (host->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(host->read_id_bytes);
        ndcr |= NDCR_SPARE_EN; /* enable spare by default */

        info->reg_ndcr = ndcr;

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

static int pxa3xx_nand_detect_config(struct pxa3xx_nand_info *info)
{
        /*
         * We set 0 by hard coding here, for we don't support keep_config
         * when there is more than one chip attached to the controller
         */
        struct pxa3xx_nand_host *host = info->host[0];
        uint32_t ndcr = nand_readl(info, NDCR);

        if (ndcr & NDCR_PAGE_SZ) {
                /* Controller's FIFO size */
                info->chunk_size = 2048;
                host->read_id_bytes = 4;
        } else {
                info->chunk_size = 512;
                host->read_id_bytes = 2;
        }

        /* Set an initial chunk size */
        info->reg_ndcr = ndcr & ~NDCR_INT_MASK;
        info->ndtr0cs0 = nand_readl(info, NDTR0CS0);
        info->ndtr1cs0 = nand_readl(info, NDTR1CS0);
        return 0;
}

#ifdef ARCH_HAS_DMA
static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
{
        struct platform_device *pdev = info->pdev;
        int data_desc_offset = info->buf_size - sizeof(struct pxa_dma_desc);

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

        info->data_buff = dma_alloc_coherent(&pdev->dev, info->buf_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_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->buf_size,
                                info->data_buff, info->data_buff_phys);
                return info->data_dma_ch;
        }

        /*
         * 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)
{
        struct platform_device *pdev = info->pdev;
        if (info->use_dma) {
                pxa_free_dma(info->data_dma_ch);
                dma_free_coherent(&pdev->dev, info->buf_size,
                                  info->data_buff, info->data_buff_phys);
        } else {
                kfree(info->data_buff);
        }
}
#else
static int pxa3xx_nand_init_buff(struct pxa3xx_nand_info *info)
{
        info->data_buff = kmalloc(info->buf_size, GFP_KERNEL);
        if (info->data_buff == NULL)
                return -ENOMEM;
        return 0;
}

static void pxa3xx_nand_free_buff(struct pxa3xx_nand_info *info)
{
        kfree(info->data_buff);
}
#endif

static int pxa3xx_nand_sensing(struct pxa3xx_nand_info *info)
{
        struct mtd_info *mtd;
        struct nand_chip *chip;
        int ret;

        mtd = info->host[info->cs]->mtd;
        chip = mtd->priv;

        /* use the common timing to make a try */
        ret = pxa3xx_nand_config_flash(info, &builtin_flash_types[0]);
        if (ret)
                return ret;

        chip->cmdfunc(mtd, NAND_CMD_RESET, 0, 0);
        ret = chip->waitfunc(mtd, chip);
        if (ret & NAND_STATUS_FAIL)
                return -ENODEV;

        return 0;
}

static int pxa_ecc_init(struct pxa3xx_nand_info *info,
                        struct nand_ecc_ctrl *ecc,
                        int strength, int ecc_stepsize, int page_size)
{
        if (strength == 1 && ecc_stepsize == 512 && page_size == 2048) {
                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->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->chunk_size = 2048;
                info->spare_size = 32;
                info->ecc_size = 32;
                ecc->mode = NAND_ECC_HW;
                ecc->size = info->chunk_size;
                ecc->layout = &ecc_layout_2KB_bch4bit;
                ecc->strength = 16;

        } else if (strength == 4 && ecc_stepsize == 512 && page_size == 4096) {
                info->ecc_bch = 1;
                info->chunk_size = 2048;
                info->spare_size = 32;
                info->ecc_size = 32;
                ecc->mode = NAND_ECC_HW;
                ecc->size = info->chunk_size;
                ecc->layout = &ecc_layout_4KB_bch4bit;
                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->chunk_size = 1024;
                info->spare_size = 0;
                info->ecc_size = 32;
                ecc->mode = NAND_ECC_HW;
                ecc->size = info->chunk_size;
                ecc->layout = &ecc_layout_4KB_bch8bit;
                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 pxa3xx_nand_host *host = mtd->priv;
        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);
        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;
        uint16_t ecc_strength, ecc_step;

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

        ret = pxa3xx_nand_sensing(info);
        if (ret) {
                dev_info(&info->pdev->dev, "There is no chip on cs %d!\n",
                         info->cs);

                return ret;
        }

        chip->cmdfunc(mtd, NAND_CMD_READID, 0, 0);
        id = *((uint16_t *)(info->data_buff));
        if (id != 0)
                dev_info(&info->pdev->dev, "Detect a flash id %x\n", id);
        else {
                dev_warn(&info->pdev->dev,
                         "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)) {
                dev_err(&info->pdev->dev, "ERROR!! flash not defined!!!\n");

                return -EINVAL;
        }

        ret = pxa3xx_nand_config_flash(info, f);
        if (ret) {
                dev_err(&info->pdev->dev, "ERROR! Configure failed\n");
                return ret;
        }

        pxa3xx_flash_ids[0].name = f->name;
        pxa3xx_flash_ids[0].dev_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 (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 (nand_scan_ident(mtd, 1, def))
                return -ENODEV;

        if (pdata->flash_bbt) {
                /*
                 * 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_USE_FLASH |
                                     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;
                }
        }

        if (pdata->ecc_strength && pdata->ecc_step_size) {
                ecc_strength = pdata->ecc_strength;
                ecc_step = pdata->ecc_step_size;
        } else {
                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, &chip->ecc, 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;
        return nand_scan_tail(mtd);
}

static int alloc_nand_resource(struct platform_device *pdev)
{
        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);
        info = devm_kzalloc(&pdev->dev, sizeof(*info) + (sizeof(*mtd) +
                            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++) {
                mtd = (struct mtd_info *)((unsigned int)&info[1] +
                      (sizeof(*mtd) + sizeof(*host)) * cs);
                chip = (struct nand_chip *)(&mtd[1]);
                host = (struct pxa3xx_nand_host *)chip;
                info->host[cs] = host;
                host->mtd = mtd;
                host->cs = cs;
                host->info_data = info;
                mtd->priv = host;
                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->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;
        }

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

        if (use_dma) {
                /*
                 * This is a dirty hack to make this driver work from
                 * devicetree bindings. It can be removed once we have
                 * a prober DMA controller framework for DT.
                 */
                if (pdev->dev.of_node &&
                    of_machine_is_compatible("marvell,pxa3xx")) {
                        info->drcmr_dat = 97;
                        info->drcmr_cmd = 99;
                } else {
                        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;

                        r = platform_get_resource(pdev, IORESOURCE_DMA, 1);
                        if (r == NULL) {
                                dev_err(&pdev->dev,
                                        "no resource defined for cmd DMA\n");
                                ret = -ENXIO;
                                goto fail_disable_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_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);
                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_irq(irq, pxa3xx_nand_irq, 0, 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 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);

        clk_disable_unprepare(info->clk);

        for (cs = 0; cs < pdata->num_cs; cs++)
                nand_release(info->host[cs]->mtd);
        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);
        pdata->flash_bbt = of_get_nand_on_flash_bbt(np);

        pdata->ecc_strength = of_get_nand_ecc_strength(np);
        if (pdata->ecc_strength < 0)
                pdata->ecc_strength = 0;

        pdata->ecc_step_size = of_get_nand_ecc_step_size(np);
        if (pdata->ecc_step_size < 0)
                pdata->ecc_step_size = 0;

        pdev->dev.platform_data = pdata;

        return 0;
}

static int pxa3xx_nand_probe(struct platform_device *pdev)
{
        struct pxa3xx_nand_platform_data *pdata;
        struct mtd_part_parser_data ppdata = {};
        struct pxa3xx_nand_info *info;
        int ret, cs, probe_success;

#ifndef ARCH_HAS_DMA
        if (use_dma) {
                use_dma = 0;
                dev_warn(&pdev->dev,
                         "This platform can't do DMA on this device\n");
        }
#endif
        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) {
                dev_err(&pdev->dev, "alloc nand resource failed\n");
                return ret;
        }

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

                /*
                 * 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;
                }

                ppdata.of_node = pdev->dev.of_node;
                ret = mtd_device_parse_register(mtd, NULL,
                                                &ppdata, 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 platform_device *pdev, pm_message_t state)
{
        struct pxa3xx_nand_info *info = platform_get_drvdata(pdev);
        struct pxa3xx_nand_platform_data *pdata;
        struct mtd_info *mtd;
        int cs;

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

        for (cs = 0; cs < pdata->num_cs; cs++) {
                mtd = info->host[cs]->mtd;
                mtd_suspend(mtd);
        }

        return 0;
}

static int pxa3xx_nand_resume(struct platform_device *pdev)
{
        struct pxa3xx_nand_info *info = platform_get_drvdata(pdev);
        struct pxa3xx_nand_platform_data *pdata;
        struct mtd_info *mtd;
        int cs;

        pdata = dev_get_platdata(&pdev->dev);
        /* 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);
        for (cs = 0; cs < pdata->num_cs; cs++) {
                mtd = info->host[cs]->mtd;
                mtd_resume(mtd);
        }

        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",
                .of_match_table = pxa3xx_nand_dt_ids,
        },
        .probe          = pxa3xx_nand_probe,
        .remove         = pxa3xx_nand_remove,
        .suspend        = pxa3xx_nand_suspend,
        .resume         = pxa3xx_nand_resume,
};

module_platform_driver(pxa3xx_nand_driver);

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