root/drivers/mtd/nand/onenand/onenand_samsung.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Samsung S3C64XX/S5PC1XX OneNAND driver
 *
 *  Copyright © 2008-2010 Samsung Electronics
 *  Kyungmin Park <kyungmin.park@samsung.com>
 *  Marek Szyprowski <m.szyprowski@samsung.com>
 *
 * Implementation:
 *      S3C64XX: emulate the pseudo BufferRAM
 *      S5PC110: use DMA
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/onenand.h>
#include <linux/mtd/partitions.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/io.h>

#include "samsung.h"

enum soc_type {
        TYPE_S3C6400,
        TYPE_S3C6410,
        TYPE_S5PC110,
};

#define ONENAND_ERASE_STATUS            0x00
#define ONENAND_MULTI_ERASE_SET         0x01
#define ONENAND_ERASE_START             0x03
#define ONENAND_UNLOCK_START            0x08
#define ONENAND_UNLOCK_END              0x09
#define ONENAND_LOCK_START              0x0A
#define ONENAND_LOCK_END                0x0B
#define ONENAND_LOCK_TIGHT_START        0x0C
#define ONENAND_LOCK_TIGHT_END          0x0D
#define ONENAND_UNLOCK_ALL              0x0E
#define ONENAND_OTP_ACCESS              0x12
#define ONENAND_SPARE_ACCESS_ONLY       0x13
#define ONENAND_MAIN_ACCESS_ONLY        0x14
#define ONENAND_ERASE_VERIFY            0x15
#define ONENAND_MAIN_SPARE_ACCESS       0x16
#define ONENAND_PIPELINE_READ           0x4000

#define MAP_00                          (0x0)
#define MAP_01                          (0x1)
#define MAP_10                          (0x2)
#define MAP_11                          (0x3)

#define S3C64XX_CMD_MAP_SHIFT           24

#define S3C6400_FBA_SHIFT               10
#define S3C6400_FPA_SHIFT               4
#define S3C6400_FSA_SHIFT               2

#define S3C6410_FBA_SHIFT               12
#define S3C6410_FPA_SHIFT               6
#define S3C6410_FSA_SHIFT               4

/* S5PC110 specific definitions */
#define S5PC110_DMA_SRC_ADDR            0x400
#define S5PC110_DMA_SRC_CFG             0x404
#define S5PC110_DMA_DST_ADDR            0x408
#define S5PC110_DMA_DST_CFG             0x40C
#define S5PC110_DMA_TRANS_SIZE          0x414
#define S5PC110_DMA_TRANS_CMD           0x418
#define S5PC110_DMA_TRANS_STATUS        0x41C
#define S5PC110_DMA_TRANS_DIR           0x420
#define S5PC110_INTC_DMA_CLR            0x1004
#define S5PC110_INTC_ONENAND_CLR        0x1008
#define S5PC110_INTC_DMA_MASK           0x1024
#define S5PC110_INTC_ONENAND_MASK       0x1028
#define S5PC110_INTC_DMA_PEND           0x1044
#define S5PC110_INTC_ONENAND_PEND       0x1048
#define S5PC110_INTC_DMA_STATUS         0x1064
#define S5PC110_INTC_ONENAND_STATUS     0x1068

#define S5PC110_INTC_DMA_TD             (1 << 24)
#define S5PC110_INTC_DMA_TE             (1 << 16)

#define S5PC110_DMA_CFG_SINGLE          (0x0 << 16)
#define S5PC110_DMA_CFG_4BURST          (0x2 << 16)
#define S5PC110_DMA_CFG_8BURST          (0x3 << 16)
#define S5PC110_DMA_CFG_16BURST         (0x4 << 16)

#define S5PC110_DMA_CFG_INC             (0x0 << 8)
#define S5PC110_DMA_CFG_CNT             (0x1 << 8)

#define S5PC110_DMA_CFG_8BIT            (0x0 << 0)
#define S5PC110_DMA_CFG_16BIT           (0x1 << 0)
#define S5PC110_DMA_CFG_32BIT           (0x2 << 0)

#define S5PC110_DMA_SRC_CFG_READ        (S5PC110_DMA_CFG_16BURST | \
                                        S5PC110_DMA_CFG_INC | \
                                        S5PC110_DMA_CFG_16BIT)
#define S5PC110_DMA_DST_CFG_READ        (S5PC110_DMA_CFG_16BURST | \
                                        S5PC110_DMA_CFG_INC | \
                                        S5PC110_DMA_CFG_32BIT)
#define S5PC110_DMA_SRC_CFG_WRITE       (S5PC110_DMA_CFG_16BURST | \
                                        S5PC110_DMA_CFG_INC | \
                                        S5PC110_DMA_CFG_32BIT)
#define S5PC110_DMA_DST_CFG_WRITE       (S5PC110_DMA_CFG_16BURST | \
                                        S5PC110_DMA_CFG_INC | \
                                        S5PC110_DMA_CFG_16BIT)

#define S5PC110_DMA_TRANS_CMD_TDC       (0x1 << 18)
#define S5PC110_DMA_TRANS_CMD_TEC       (0x1 << 16)
#define S5PC110_DMA_TRANS_CMD_TR        (0x1 << 0)

#define S5PC110_DMA_TRANS_STATUS_TD     (0x1 << 18)
#define S5PC110_DMA_TRANS_STATUS_TB     (0x1 << 17)
#define S5PC110_DMA_TRANS_STATUS_TE     (0x1 << 16)

#define S5PC110_DMA_DIR_READ            0x0
#define S5PC110_DMA_DIR_WRITE           0x1

struct s3c_onenand {
        struct mtd_info *mtd;
        struct platform_device  *pdev;
        enum soc_type   type;
        void __iomem    *base;
        void __iomem    *ahb_addr;
        int             bootram_command;
        void            *page_buf;
        void            *oob_buf;
        unsigned int    (*mem_addr)(int fba, int fpa, int fsa);
        unsigned int    (*cmd_map)(unsigned int type, unsigned int val);
        void __iomem    *dma_addr;
        unsigned long   phys_base;
        struct completion       complete;
};

#define CMD_MAP_00(dev, addr)           (dev->cmd_map(MAP_00, ((addr) << 1)))
#define CMD_MAP_01(dev, mem_addr)       (dev->cmd_map(MAP_01, (mem_addr)))
#define CMD_MAP_10(dev, mem_addr)       (dev->cmd_map(MAP_10, (mem_addr)))
#define CMD_MAP_11(dev, addr)           (dev->cmd_map(MAP_11, ((addr) << 2)))

static struct s3c_onenand *onenand;

static inline int s3c_read_reg(int offset)
{
        return readl(onenand->base + offset);
}

static inline void s3c_write_reg(int value, int offset)
{
        writel(value, onenand->base + offset);
}

static inline int s3c_read_cmd(unsigned int cmd)
{
        return readl(onenand->ahb_addr + cmd);
}

static inline void s3c_write_cmd(int value, unsigned int cmd)
{
        writel(value, onenand->ahb_addr + cmd);
}

#ifdef SAMSUNG_DEBUG
static void s3c_dump_reg(void)
{
        int i;

        for (i = 0; i < 0x400; i += 0x40) {
                printk(KERN_INFO "0x%08X: 0x%08x 0x%08x 0x%08x 0x%08x\n",
                        (unsigned int) onenand->base + i,
                        s3c_read_reg(i), s3c_read_reg(i + 0x10),
                        s3c_read_reg(i + 0x20), s3c_read_reg(i + 0x30));
        }
}
#endif

static unsigned int s3c64xx_cmd_map(unsigned type, unsigned val)
{
        return (type << S3C64XX_CMD_MAP_SHIFT) | val;
}

static unsigned int s3c6400_mem_addr(int fba, int fpa, int fsa)
{
        return (fba << S3C6400_FBA_SHIFT) | (fpa << S3C6400_FPA_SHIFT) |
                (fsa << S3C6400_FSA_SHIFT);
}

static unsigned int s3c6410_mem_addr(int fba, int fpa, int fsa)
{
        return (fba << S3C6410_FBA_SHIFT) | (fpa << S3C6410_FPA_SHIFT) |
                (fsa << S3C6410_FSA_SHIFT);
}

static void s3c_onenand_reset(void)
{
        unsigned long timeout = 0x10000;
        int stat;

        s3c_write_reg(ONENAND_MEM_RESET_COLD, MEM_RESET_OFFSET);
        while (1 && timeout--) {
                stat = s3c_read_reg(INT_ERR_STAT_OFFSET);
                if (stat & RST_CMP)
                        break;
        }
        stat = s3c_read_reg(INT_ERR_STAT_OFFSET);
        s3c_write_reg(stat, INT_ERR_ACK_OFFSET);

        /* Clear interrupt */
        s3c_write_reg(0x0, INT_ERR_ACK_OFFSET);
        /* Clear the ECC status */
        s3c_write_reg(0x0, ECC_ERR_STAT_OFFSET);
}

static unsigned short s3c_onenand_readw(void __iomem *addr)
{
        struct onenand_chip *this = onenand->mtd->priv;
        struct device *dev = &onenand->pdev->dev;
        int reg = addr - this->base;
        int word_addr = reg >> 1;
        int value;

        /* It's used for probing time */
        switch (reg) {
        case ONENAND_REG_MANUFACTURER_ID:
                return s3c_read_reg(MANUFACT_ID_OFFSET);
        case ONENAND_REG_DEVICE_ID:
                return s3c_read_reg(DEVICE_ID_OFFSET);
        case ONENAND_REG_VERSION_ID:
                return s3c_read_reg(FLASH_VER_ID_OFFSET);
        case ONENAND_REG_DATA_BUFFER_SIZE:
                return s3c_read_reg(DATA_BUF_SIZE_OFFSET);
        case ONENAND_REG_TECHNOLOGY:
                return s3c_read_reg(TECH_OFFSET);
        case ONENAND_REG_SYS_CFG1:
                return s3c_read_reg(MEM_CFG_OFFSET);

        /* Used at unlock all status */
        case ONENAND_REG_CTRL_STATUS:
                return 0;

        case ONENAND_REG_WP_STATUS:
                return ONENAND_WP_US;

        default:
                break;
        }

        /* BootRAM access control */
        if ((unsigned long)addr < ONENAND_DATARAM && onenand->bootram_command) {
                if (word_addr == 0)
                        return s3c_read_reg(MANUFACT_ID_OFFSET);
                if (word_addr == 1)
                        return s3c_read_reg(DEVICE_ID_OFFSET);
                if (word_addr == 2)
                        return s3c_read_reg(FLASH_VER_ID_OFFSET);
        }

        value = s3c_read_cmd(CMD_MAP_11(onenand, word_addr)) & 0xffff;
        dev_info(dev, "%s: Illegal access at reg 0x%x, value 0x%x\n", __func__,
                 word_addr, value);
        return value;
}

static void s3c_onenand_writew(unsigned short value, void __iomem *addr)
{
        struct onenand_chip *this = onenand->mtd->priv;
        struct device *dev = &onenand->pdev->dev;
        unsigned int reg = addr - this->base;
        unsigned int word_addr = reg >> 1;

        /* It's used for probing time */
        switch (reg) {
        case ONENAND_REG_SYS_CFG1:
                s3c_write_reg(value, MEM_CFG_OFFSET);
                return;

        case ONENAND_REG_START_ADDRESS1:
        case ONENAND_REG_START_ADDRESS2:
                return;

        /* Lock/lock-tight/unlock/unlock_all */
        case ONENAND_REG_START_BLOCK_ADDRESS:
                return;

        default:
                break;
        }

        /* BootRAM access control */
        if ((unsigned long)addr < ONENAND_DATARAM) {
                if (value == ONENAND_CMD_READID) {
                        onenand->bootram_command = 1;
                        return;
                }
                if (value == ONENAND_CMD_RESET) {
                        s3c_write_reg(ONENAND_MEM_RESET_COLD, MEM_RESET_OFFSET);
                        onenand->bootram_command = 0;
                        return;
                }
        }

        dev_info(dev, "%s: Illegal access at reg 0x%x, value 0x%x\n", __func__,
                 word_addr, value);

        s3c_write_cmd(value, CMD_MAP_11(onenand, word_addr));
}

static int s3c_onenand_wait(struct mtd_info *mtd, int state)
{
        struct device *dev = &onenand->pdev->dev;
        unsigned int flags = INT_ACT;
        unsigned int stat, ecc;
        unsigned long timeout;

        switch (state) {
        case FL_READING:
                flags |= BLK_RW_CMP | LOAD_CMP;
                break;
        case FL_WRITING:
                flags |= BLK_RW_CMP | PGM_CMP;
                break;
        case FL_ERASING:
                flags |= BLK_RW_CMP | ERS_CMP;
                break;
        case FL_LOCKING:
                flags |= BLK_RW_CMP;
                break;
        default:
                break;
        }

        /* The 20 msec is enough */
        timeout = jiffies + msecs_to_jiffies(20);
        while (time_before(jiffies, timeout)) {
                stat = s3c_read_reg(INT_ERR_STAT_OFFSET);
                if (stat & flags)
                        break;

                if (state != FL_READING)
                        cond_resched();
        }
        /* To get correct interrupt status in timeout case */
        stat = s3c_read_reg(INT_ERR_STAT_OFFSET);
        s3c_write_reg(stat, INT_ERR_ACK_OFFSET);

        /*
         * In the Spec. it checks the controller status first
         * However if you get the correct information in case of
         * power off recovery (POR) test, it should read ECC status first
         */
        if (stat & LOAD_CMP) {
                ecc = s3c_read_reg(ECC_ERR_STAT_OFFSET);
                if (ecc & ONENAND_ECC_4BIT_UNCORRECTABLE) {
                        dev_info(dev, "%s: ECC error = 0x%04x\n", __func__,
                                 ecc);
                        mtd->ecc_stats.failed++;
                        return -EBADMSG;
                }
        }

        if (stat & (LOCKED_BLK | ERS_FAIL | PGM_FAIL | LD_FAIL_ECC_ERR)) {
                dev_info(dev, "%s: controller error = 0x%04x\n", __func__,
                         stat);
                if (stat & LOCKED_BLK)
                        dev_info(dev, "%s: it's locked error = 0x%04x\n",
                                 __func__, stat);

                return -EIO;
        }

        return 0;
}

static int s3c_onenand_command(struct mtd_info *mtd, int cmd, loff_t addr,
                               size_t len)
{
        struct onenand_chip *this = mtd->priv;
        unsigned int *m, *s;
        int fba, fpa, fsa = 0;
        unsigned int mem_addr, cmd_map_01, cmd_map_10;
        int i, mcount, scount;
        int index;

        fba = (int) (addr >> this->erase_shift);
        fpa = (int) (addr >> this->page_shift);
        fpa &= this->page_mask;

        mem_addr = onenand->mem_addr(fba, fpa, fsa);
        cmd_map_01 = CMD_MAP_01(onenand, mem_addr);
        cmd_map_10 = CMD_MAP_10(onenand, mem_addr);

        switch (cmd) {
        case ONENAND_CMD_READ:
        case ONENAND_CMD_READOOB:
        case ONENAND_CMD_BUFFERRAM:
                ONENAND_SET_NEXT_BUFFERRAM(this);
                break;
        default:
                break;
        }

        index = ONENAND_CURRENT_BUFFERRAM(this);

        /*
         * Emulate Two BufferRAMs and access with 4 bytes pointer
         */
        m = onenand->page_buf;
        s = onenand->oob_buf;

        if (index) {
                m += (this->writesize >> 2);
                s += (mtd->oobsize >> 2);
        }

        mcount = mtd->writesize >> 2;
        scount = mtd->oobsize >> 2;

        switch (cmd) {
        case ONENAND_CMD_READ:
                /* Main */
                for (i = 0; i < mcount; i++)
                        *m++ = s3c_read_cmd(cmd_map_01);
                return 0;

        case ONENAND_CMD_READOOB:
                s3c_write_reg(TSRF, TRANS_SPARE_OFFSET);
                /* Main */
                for (i = 0; i < mcount; i++)
                        *m++ = s3c_read_cmd(cmd_map_01);

                /* Spare */
                for (i = 0; i < scount; i++)
                        *s++ = s3c_read_cmd(cmd_map_01);

                s3c_write_reg(0, TRANS_SPARE_OFFSET);
                return 0;

        case ONENAND_CMD_PROG:
                /* Main */
                for (i = 0; i < mcount; i++)
                        s3c_write_cmd(*m++, cmd_map_01);
                return 0;

        case ONENAND_CMD_PROGOOB:
                s3c_write_reg(TSRF, TRANS_SPARE_OFFSET);

                /* Main - dummy write */
                for (i = 0; i < mcount; i++)
                        s3c_write_cmd(0xffffffff, cmd_map_01);

                /* Spare */
                for (i = 0; i < scount; i++)
                        s3c_write_cmd(*s++, cmd_map_01);

                s3c_write_reg(0, TRANS_SPARE_OFFSET);
                return 0;

        case ONENAND_CMD_UNLOCK_ALL:
                s3c_write_cmd(ONENAND_UNLOCK_ALL, cmd_map_10);
                return 0;

        case ONENAND_CMD_ERASE:
                s3c_write_cmd(ONENAND_ERASE_START, cmd_map_10);
                return 0;

        default:
                break;
        }

        return 0;
}

static unsigned char *s3c_get_bufferram(struct mtd_info *mtd, int area)
{
        struct onenand_chip *this = mtd->priv;
        int index = ONENAND_CURRENT_BUFFERRAM(this);
        unsigned char *p;

        if (area == ONENAND_DATARAM) {
                p = onenand->page_buf;
                if (index == 1)
                        p += this->writesize;
        } else {
                p = onenand->oob_buf;
                if (index == 1)
                        p += mtd->oobsize;
        }

        return p;
}

static int onenand_read_bufferram(struct mtd_info *mtd, int area,
                                  unsigned char *buffer, int offset,
                                  size_t count)
{
        unsigned char *p;

        p = s3c_get_bufferram(mtd, area);
        memcpy(buffer, p + offset, count);
        return 0;
}

static int onenand_write_bufferram(struct mtd_info *mtd, int area,
                                   const unsigned char *buffer, int offset,
                                   size_t count)
{
        unsigned char *p;

        p = s3c_get_bufferram(mtd, area);
        memcpy(p + offset, buffer, count);
        return 0;
}

static int (*s5pc110_dma_ops)(dma_addr_t dst, dma_addr_t src, size_t count, int direction);

static int s5pc110_dma_poll(dma_addr_t dst, dma_addr_t src, size_t count, int direction)
{
        void __iomem *base = onenand->dma_addr;
        int status;
        unsigned long timeout;

        writel(src, base + S5PC110_DMA_SRC_ADDR);
        writel(dst, base + S5PC110_DMA_DST_ADDR);

        if (direction == S5PC110_DMA_DIR_READ) {
                writel(S5PC110_DMA_SRC_CFG_READ, base + S5PC110_DMA_SRC_CFG);
                writel(S5PC110_DMA_DST_CFG_READ, base + S5PC110_DMA_DST_CFG);
        } else {
                writel(S5PC110_DMA_SRC_CFG_WRITE, base + S5PC110_DMA_SRC_CFG);
                writel(S5PC110_DMA_DST_CFG_WRITE, base + S5PC110_DMA_DST_CFG);
        }

        writel(count, base + S5PC110_DMA_TRANS_SIZE);
        writel(direction, base + S5PC110_DMA_TRANS_DIR);

        writel(S5PC110_DMA_TRANS_CMD_TR, base + S5PC110_DMA_TRANS_CMD);

        /*
         * There's no exact timeout values at Spec.
         * In real case it takes under 1 msec.
         * So 20 msecs are enough.
         */
        timeout = jiffies + msecs_to_jiffies(20);

        do {
                status = readl(base + S5PC110_DMA_TRANS_STATUS);
                if (status & S5PC110_DMA_TRANS_STATUS_TE) {
                        writel(S5PC110_DMA_TRANS_CMD_TEC,
                                        base + S5PC110_DMA_TRANS_CMD);
                        return -EIO;
                }
        } while (!(status & S5PC110_DMA_TRANS_STATUS_TD) &&
                time_before(jiffies, timeout));

        writel(S5PC110_DMA_TRANS_CMD_TDC, base + S5PC110_DMA_TRANS_CMD);

        return 0;
}

static irqreturn_t s5pc110_onenand_irq(int irq, void *data)
{
        void __iomem *base = onenand->dma_addr;
        int status, cmd = 0;

        status = readl(base + S5PC110_INTC_DMA_STATUS);

        if (likely(status & S5PC110_INTC_DMA_TD))
                cmd = S5PC110_DMA_TRANS_CMD_TDC;

        if (unlikely(status & S5PC110_INTC_DMA_TE))
                cmd = S5PC110_DMA_TRANS_CMD_TEC;

        writel(cmd, base + S5PC110_DMA_TRANS_CMD);
        writel(status, base + S5PC110_INTC_DMA_CLR);

        if (!onenand->complete.done)
                complete(&onenand->complete);

        return IRQ_HANDLED;
}

static int s5pc110_dma_irq(dma_addr_t dst, dma_addr_t src, size_t count, int direction)
{
        void __iomem *base = onenand->dma_addr;
        int status;

        status = readl(base + S5PC110_INTC_DMA_MASK);
        if (status) {
                status &= ~(S5PC110_INTC_DMA_TD | S5PC110_INTC_DMA_TE);
                writel(status, base + S5PC110_INTC_DMA_MASK);
        }

        writel(src, base + S5PC110_DMA_SRC_ADDR);
        writel(dst, base + S5PC110_DMA_DST_ADDR);

        if (direction == S5PC110_DMA_DIR_READ) {
                writel(S5PC110_DMA_SRC_CFG_READ, base + S5PC110_DMA_SRC_CFG);
                writel(S5PC110_DMA_DST_CFG_READ, base + S5PC110_DMA_DST_CFG);
        } else {
                writel(S5PC110_DMA_SRC_CFG_WRITE, base + S5PC110_DMA_SRC_CFG);
                writel(S5PC110_DMA_DST_CFG_WRITE, base + S5PC110_DMA_DST_CFG);
        }

        writel(count, base + S5PC110_DMA_TRANS_SIZE);
        writel(direction, base + S5PC110_DMA_TRANS_DIR);

        writel(S5PC110_DMA_TRANS_CMD_TR, base + S5PC110_DMA_TRANS_CMD);

        wait_for_completion_timeout(&onenand->complete, msecs_to_jiffies(20));

        return 0;
}

static int s5pc110_read_bufferram(struct mtd_info *mtd, int area,
                unsigned char *buffer, int offset, size_t count)
{
        struct onenand_chip *this = mtd->priv;
        void __iomem *p;
        void *buf = (void *) buffer;
        dma_addr_t dma_src, dma_dst;
        int err, ofs, page_dma = 0;
        struct device *dev = &onenand->pdev->dev;

        p = this->base + area;
        if (ONENAND_CURRENT_BUFFERRAM(this)) {
                if (area == ONENAND_DATARAM)
                        p += this->writesize;
                else
                        p += mtd->oobsize;
        }

        if (offset & 3 || (size_t) buf & 3 ||
                !onenand->dma_addr || count != mtd->writesize)
                goto normal;

        /* Handle vmalloc address */
        if (buf >= high_memory) {
                struct page *page;

                if (((size_t) buf & PAGE_MASK) !=
                    ((size_t) (buf + count - 1) & PAGE_MASK))
                        goto normal;
                page = vmalloc_to_page(buf);
                if (!page)
                        goto normal;

                /* Page offset */
                ofs = ((size_t) buf & ~PAGE_MASK);
                page_dma = 1;

                /* DMA routine */
                dma_src = onenand->phys_base + (p - this->base);
                dma_dst = dma_map_page(dev, page, ofs, count, DMA_FROM_DEVICE);
        } else {
                /* DMA routine */
                dma_src = onenand->phys_base + (p - this->base);
                dma_dst = dma_map_single(dev, buf, count, DMA_FROM_DEVICE);
        }
        if (dma_mapping_error(dev, dma_dst)) {
                dev_err(dev, "Couldn't map a %zu byte buffer for DMA\n", count);
                goto normal;
        }
        err = s5pc110_dma_ops(dma_dst, dma_src,
                        count, S5PC110_DMA_DIR_READ);

        if (page_dma)
                dma_unmap_page(dev, dma_dst, count, DMA_FROM_DEVICE);
        else
                dma_unmap_single(dev, dma_dst, count, DMA_FROM_DEVICE);

        if (!err)
                return 0;

normal:
        if (count != mtd->writesize) {
                /* Copy the bufferram to memory to prevent unaligned access */
                memcpy_fromio(this->page_buf, p, mtd->writesize);
                memcpy(buffer, this->page_buf + offset, count);
        } else {
                memcpy_fromio(buffer, p, count);
        }

        return 0;
}

static int s5pc110_chip_probe(struct mtd_info *mtd)
{
        /* Now just return 0 */
        return 0;
}

static int s3c_onenand_bbt_wait(struct mtd_info *mtd, int state)
{
        unsigned int flags = INT_ACT | LOAD_CMP;
        unsigned int stat;
        unsigned long timeout;

        /* The 20 msec is enough */
        timeout = jiffies + msecs_to_jiffies(20);
        while (time_before(jiffies, timeout)) {
                stat = s3c_read_reg(INT_ERR_STAT_OFFSET);
                if (stat & flags)
                        break;
        }
        /* To get correct interrupt status in timeout case */
        stat = s3c_read_reg(INT_ERR_STAT_OFFSET);
        s3c_write_reg(stat, INT_ERR_ACK_OFFSET);

        if (stat & LD_FAIL_ECC_ERR) {
                s3c_onenand_reset();
                return ONENAND_BBT_READ_ERROR;
        }

        if (stat & LOAD_CMP) {
                int ecc = s3c_read_reg(ECC_ERR_STAT_OFFSET);
                if (ecc & ONENAND_ECC_4BIT_UNCORRECTABLE) {
                        s3c_onenand_reset();
                        return ONENAND_BBT_READ_ERROR;
                }
        }

        return 0;
}

static void s3c_onenand_check_lock_status(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;
        struct device *dev = &onenand->pdev->dev;
        unsigned int block, end;

        end = this->chipsize >> this->erase_shift;

        for (block = 0; block < end; block++) {
                unsigned int mem_addr = onenand->mem_addr(block, 0, 0);
                s3c_read_cmd(CMD_MAP_01(onenand, mem_addr));

                if (s3c_read_reg(INT_ERR_STAT_OFFSET) & LOCKED_BLK) {
                        dev_err(dev, "block %d is write-protected!\n", block);
                        s3c_write_reg(LOCKED_BLK, INT_ERR_ACK_OFFSET);
                }
        }
}

static void s3c_onenand_do_lock_cmd(struct mtd_info *mtd, loff_t ofs,
                                    size_t len, int cmd)
{
        struct onenand_chip *this = mtd->priv;
        int start, end, start_mem_addr, end_mem_addr;

        start = ofs >> this->erase_shift;
        start_mem_addr = onenand->mem_addr(start, 0, 0);
        end = start + (len >> this->erase_shift) - 1;
        end_mem_addr = onenand->mem_addr(end, 0, 0);

        if (cmd == ONENAND_CMD_LOCK) {
                s3c_write_cmd(ONENAND_LOCK_START, CMD_MAP_10(onenand,
                                                             start_mem_addr));
                s3c_write_cmd(ONENAND_LOCK_END, CMD_MAP_10(onenand,
                                                           end_mem_addr));
        } else {
                s3c_write_cmd(ONENAND_UNLOCK_START, CMD_MAP_10(onenand,
                                                               start_mem_addr));
                s3c_write_cmd(ONENAND_UNLOCK_END, CMD_MAP_10(onenand,
                                                             end_mem_addr));
        }

        this->wait(mtd, FL_LOCKING);
}

static void s3c_unlock_all(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;
        loff_t ofs = 0;
        size_t len = this->chipsize;

        if (this->options & ONENAND_HAS_UNLOCK_ALL) {
                /* Write unlock command */
                this->command(mtd, ONENAND_CMD_UNLOCK_ALL, 0, 0);

                /* No need to check return value */
                this->wait(mtd, FL_LOCKING);

                /* Workaround for all block unlock in DDP */
                if (!ONENAND_IS_DDP(this)) {
                        s3c_onenand_check_lock_status(mtd);
                        return;
                }

                /* All blocks on another chip */
                ofs = this->chipsize >> 1;
                len = this->chipsize >> 1;
        }

        s3c_onenand_do_lock_cmd(mtd, ofs, len, ONENAND_CMD_UNLOCK);

        s3c_onenand_check_lock_status(mtd);
}

static void s3c_onenand_setup(struct mtd_info *mtd)
{
        struct onenand_chip *this = mtd->priv;

        onenand->mtd = mtd;

        if (onenand->type == TYPE_S3C6400) {
                onenand->mem_addr = s3c6400_mem_addr;
                onenand->cmd_map = s3c64xx_cmd_map;
        } else if (onenand->type == TYPE_S3C6410) {
                onenand->mem_addr = s3c6410_mem_addr;
                onenand->cmd_map = s3c64xx_cmd_map;
        } else if (onenand->type == TYPE_S5PC110) {
                /* Use generic onenand functions */
                this->read_bufferram = s5pc110_read_bufferram;
                this->chip_probe = s5pc110_chip_probe;
                return;
        } else {
                BUG();
        }

        this->read_word = s3c_onenand_readw;
        this->write_word = s3c_onenand_writew;

        this->wait = s3c_onenand_wait;
        this->bbt_wait = s3c_onenand_bbt_wait;
        this->unlock_all = s3c_unlock_all;
        this->command = s3c_onenand_command;

        this->read_bufferram = onenand_read_bufferram;
        this->write_bufferram = onenand_write_bufferram;
}

static int s3c_onenand_probe(struct platform_device *pdev)
{
        struct onenand_platform_data *pdata;
        struct onenand_chip *this;
        struct mtd_info *mtd;
        struct resource *r;
        int size, err;

        pdata = dev_get_platdata(&pdev->dev);
        /* No need to check pdata. the platform data is optional */

        size = sizeof(struct mtd_info) + sizeof(struct onenand_chip);
        mtd = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
        if (!mtd)
                return -ENOMEM;

        onenand = devm_kzalloc(&pdev->dev, sizeof(struct s3c_onenand),
                               GFP_KERNEL);
        if (!onenand)
                return -ENOMEM;

        this = (struct onenand_chip *) &mtd[1];
        mtd->priv = this;
        mtd->dev.parent = &pdev->dev;
        onenand->pdev = pdev;
        onenand->type = platform_get_device_id(pdev)->driver_data;

        s3c_onenand_setup(mtd);

        onenand->base = devm_platform_get_and_ioremap_resource(pdev, 0, &r);
        if (IS_ERR(onenand->base))
                return PTR_ERR(onenand->base);

        onenand->phys_base = r->start;

        /* Set onenand_chip also */
        this->base = onenand->base;

        /* Use runtime badblock check */
        this->options |= ONENAND_SKIP_UNLOCK_CHECK;

        if (onenand->type != TYPE_S5PC110) {
                onenand->ahb_addr = devm_platform_ioremap_resource(pdev, 1);
                if (IS_ERR(onenand->ahb_addr))
                        return PTR_ERR(onenand->ahb_addr);

                /* Allocate 4KiB BufferRAM */
                onenand->page_buf = devm_kzalloc(&pdev->dev, SZ_4K,
                                                 GFP_KERNEL);
                if (!onenand->page_buf)
                        return -ENOMEM;

                /* Allocate 128 SpareRAM */
                onenand->oob_buf = devm_kzalloc(&pdev->dev, 128, GFP_KERNEL);
                if (!onenand->oob_buf)
                        return -ENOMEM;

                /* S3C doesn't handle subpage write */
                mtd->subpage_sft = 0;
                this->subpagesize = mtd->writesize;

        } else { /* S5PC110 */
                onenand->dma_addr = devm_platform_ioremap_resource(pdev, 1);
                if (IS_ERR(onenand->dma_addr))
                        return PTR_ERR(onenand->dma_addr);

                s5pc110_dma_ops = s5pc110_dma_poll;
                /* Interrupt support */
                r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
                if (r) {
                        init_completion(&onenand->complete);
                        s5pc110_dma_ops = s5pc110_dma_irq;
                        err = devm_request_irq(&pdev->dev, r->start,
                                               s5pc110_onenand_irq,
                                               IRQF_SHARED, "onenand",
                                               onenand);
                        if (err) {
                                dev_err(&pdev->dev, "failed to get irq\n");
                                return err;
                        }
                }
        }

        err = onenand_scan(mtd, 1);
        if (err)
                return err;

        if (onenand->type != TYPE_S5PC110) {
                /* S3C doesn't handle subpage write */
                mtd->subpage_sft = 0;
                this->subpagesize = mtd->writesize;
        }

        if (s3c_read_reg(MEM_CFG_OFFSET) & ONENAND_SYS_CFG1_SYNC_READ)
                dev_info(&onenand->pdev->dev, "OneNAND Sync. Burst Read enabled\n");

        err = mtd_device_register(mtd, pdata ? pdata->parts : NULL,
                                  pdata ? pdata->nr_parts : 0);
        if (err) {
                dev_err(&pdev->dev, "failed to parse partitions and register the MTD device\n");
                onenand_release(mtd);
                return err;
        }

        platform_set_drvdata(pdev, mtd);

        return 0;
}

static void s3c_onenand_remove(struct platform_device *pdev)
{
        struct mtd_info *mtd = platform_get_drvdata(pdev);

        onenand_release(mtd);
}

static int s3c_pm_ops_suspend(struct device *dev)
{
        struct mtd_info *mtd = dev_get_drvdata(dev);
        struct onenand_chip *this = mtd->priv;

        this->wait(mtd, FL_PM_SUSPENDED);
        return 0;
}

static  int s3c_pm_ops_resume(struct device *dev)
{
        struct mtd_info *mtd = dev_get_drvdata(dev);
        struct onenand_chip *this = mtd->priv;

        this->unlock_all(mtd);
        return 0;
}

static const struct dev_pm_ops s3c_pm_ops = {
        .suspend        = s3c_pm_ops_suspend,
        .resume         = s3c_pm_ops_resume,
};

static const struct platform_device_id s3c_onenand_driver_ids[] = {
        {
                .name           = "s3c6400-onenand",
                .driver_data    = TYPE_S3C6400,
        }, {
                .name           = "s3c6410-onenand",
                .driver_data    = TYPE_S3C6410,
        }, {
                .name           = "s5pc110-onenand",
                .driver_data    = TYPE_S5PC110,
        }, { },
};
MODULE_DEVICE_TABLE(platform, s3c_onenand_driver_ids);

static struct platform_driver s3c_onenand_driver = {
        .driver         = {
                .name   = "samsung-onenand",
                .pm     = &s3c_pm_ops,
        },
        .id_table       = s3c_onenand_driver_ids,
        .probe          = s3c_onenand_probe,
        .remove         = s3c_onenand_remove,
};

module_platform_driver(s3c_onenand_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Kyungmin Park <kyungmin.park@samsung.com>");
MODULE_DESCRIPTION("Samsung OneNAND controller support");