root/drivers/mtd/nand/raw/meson_nand.c
// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
/*
 * Amlogic Meson Nand Flash Controller Driver
 *
 * Copyright (c) 2018 Amlogic, inc.
 * Author: Liang Yang <liang.yang@amlogic.com>
 */

#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/mtd.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/sched/task_stack.h>

#define NFC_REG_CMD             0x00
#define NFC_CMD_IDLE            (0xc << 14)
#define NFC_CMD_CLE             (0x5 << 14)
#define NFC_CMD_ALE             (0x6 << 14)
#define NFC_CMD_ADL             ((0 << 16) | (3 << 20))
#define NFC_CMD_ADH             ((1 << 16) | (3 << 20))
#define NFC_CMD_AIL             ((2 << 16) | (3 << 20))
#define NFC_CMD_AIH             ((3 << 16) | (3 << 20))
#define NFC_CMD_SEED            ((8 << 16) | (3 << 20))
#define NFC_CMD_M2N             ((0 << 17) | (2 << 20))
#define NFC_CMD_N2M             ((1 << 17) | (2 << 20))
#define NFC_CMD_RB              BIT(20)
#define NFC_CMD_SCRAMBLER_ENABLE        BIT(19)
#define NFC_CMD_SCRAMBLER_DISABLE       0
#define NFC_CMD_SHORTMODE_ENABLE        1
#define NFC_CMD_SHORTMODE_DISABLE       0
#define NFC_CMD_RB_INT          BIT(14)
#define NFC_CMD_RB_INT_NO_PIN   ((0xb << 10) | BIT(18) | BIT(16))

#define NFC_CMD_GET_SIZE(x)     (((x) >> 22) & GENMASK(4, 0))

#define NFC_REG_CFG             0x04
#define NFC_REG_DADR            0x08
#define NFC_REG_IADR            0x0c
#define NFC_REG_BUF             0x10
#define NFC_REG_INFO            0x14
#define NFC_REG_DC              0x18
#define NFC_REG_ADR             0x1c
#define NFC_REG_DL              0x20
#define NFC_REG_DH              0x24
#define NFC_REG_CADR            0x28
#define NFC_REG_SADR            0x2c
#define NFC_REG_PINS            0x30
#define NFC_REG_VER             0x38

#define NFC_RB_IRQ_EN           BIT(21)

#define CLK_DIV_SHIFT           0
#define CLK_DIV_WIDTH           6

#define CMDRWGEN(cmd_dir, ran, bch, short_mode, page_size, pages)       \
        (                                                               \
                (cmd_dir)                       |                       \
                (ran)                           |                       \
                ((bch) << 14)                   |                       \
                ((short_mode) << 13)            |                       \
                (((page_size) & 0x7f) << 6)     |                       \
                ((pages) & 0x3f)                                        \
        )

#define GENCMDDADDRL(adl, addr)         ((adl) | ((addr) & 0xffff))
#define GENCMDDADDRH(adh, addr)         ((adh) | (((addr) >> 16) & 0xffff))
#define GENCMDIADDRL(ail, addr)         ((ail) | ((addr) & 0xffff))
#define GENCMDIADDRH(aih, addr)         ((aih) | (((addr) >> 16) & 0xffff))

#define DMA_DIR(dir)            ((dir) ? NFC_CMD_N2M : NFC_CMD_M2N)
#define DMA_ADDR_ALIGN          8

#define NFC_SHORT_MODE_ECC_SZ   384

#define ECC_CHECK_RETURN_FF     (-1)

#define NAND_CE0                (0xe << 10)
#define NAND_CE1                (0xd << 10)

#define DMA_BUSY_TIMEOUT        0x100000
#define CMD_FIFO_EMPTY_TIMEOUT  1000

#define MAX_CE_NUM              2

/* eMMC clock register, misc control */
#define CLK_SELECT_NAND         BIT(31)
#define CLK_ALWAYS_ON_NAND      BIT(24)
#define CLK_SELECT_FIX_PLL2     BIT(6)

#define NFC_CLK_CYCLE           6

/* nand flash controller delay 3 ns */
#define NFC_DEFAULT_DELAY       3000

#define ROW_ADDER(page, index)  (((page) >> (8 * (index))) & 0xff)
#define MAX_CYCLE_ADDRS         5
#define DIRREAD                 1
#define DIRWRITE                0

#define ECC_PARITY_BCH8_512B    14
#define ECC_COMPLETE            BIT(31)
#define ECC_ERR_CNT(x)          (((x) >> 24) & GENMASK(5, 0))
#define ECC_ZERO_CNT(x)         (((x) >> 16) & GENMASK(5, 0))
#define ECC_UNCORRECTABLE       0x3f

#define PER_INFO_BYTE           8

#define NFC_CMD_RAW_LEN GENMASK(13, 0)

#define NFC_COLUMN_ADDR_0       0
#define NFC_COLUMN_ADDR_1       0

struct meson_nfc_nand_chip {
        struct list_head node;
        struct nand_chip nand;
        unsigned long clk_rate;
        unsigned long level1_divider;
        u32 bus_timing;
        u32 twb;
        u32 tadl;
        u32 tbers_max;
        u32 boot_pages;
        u32 boot_page_step;

        u32 bch_mode;
        u8 *data_buf;
        __le64 *info_buf;
        u32 nsels;
        u8 sels[] __counted_by(nsels);
};

struct meson_nand_ecc {
        u32 bch;
        u32 strength;
        u32 size;
};

struct meson_nfc_data {
        const struct nand_ecc_caps *ecc_caps;
};

struct meson_nfc_param {
        u32 chip_select;
        u32 rb_select;
};

struct nand_rw_cmd {
        u32 cmd0;
        u32 addrs[MAX_CYCLE_ADDRS];
        u32 cmd1;
};

struct nand_timing {
        u32 twb;
        u32 tadl;
        u32 tbers_max;
};

struct meson_nfc {
        struct nand_controller controller;
        struct clk *core_clk;
        struct clk *device_clk;
        struct clk *nand_clk;
        struct clk_divider nand_divider;

        unsigned long clk_rate;
        u32 bus_timing;

        struct device *dev;
        void __iomem *reg_base;
        void __iomem *reg_clk;
        struct completion completion;
        struct list_head chips;
        const struct meson_nfc_data *data;
        struct meson_nfc_param param;
        struct nand_timing timing;
        union {
                int cmd[32];
                struct nand_rw_cmd rw;
        } cmdfifo;

        dma_addr_t daddr;
        dma_addr_t iaddr;
        u32 info_bytes;

        unsigned long assigned_cs;
        bool no_rb_pin;
};

enum {
        NFC_ECC_BCH8_512        = 1,
        NFC_ECC_BCH8_1K,
        NFC_ECC_BCH24_1K,
        NFC_ECC_BCH30_1K,
        NFC_ECC_BCH40_1K,
        NFC_ECC_BCH50_1K,
        NFC_ECC_BCH60_1K,
};

#define MESON_ECC_DATA(b, s, sz)        { .bch = (b), .strength = (s), .size = (sz) }

static struct meson_nand_ecc meson_ecc[] = {
        MESON_ECC_DATA(NFC_ECC_BCH8_512, 8,  512),
        MESON_ECC_DATA(NFC_ECC_BCH8_1K,  8,  1024),
        MESON_ECC_DATA(NFC_ECC_BCH24_1K, 24, 1024),
        MESON_ECC_DATA(NFC_ECC_BCH30_1K, 30, 1024),
        MESON_ECC_DATA(NFC_ECC_BCH40_1K, 40, 1024),
        MESON_ECC_DATA(NFC_ECC_BCH50_1K, 50, 1024),
        MESON_ECC_DATA(NFC_ECC_BCH60_1K, 60, 1024),
};

static int meson_nand_calc_ecc_bytes(int step_size, int strength)
{
        int ecc_bytes;

        if (step_size == 512 && strength == 8)
                return ECC_PARITY_BCH8_512B;

        ecc_bytes = DIV_ROUND_UP(strength * fls(step_size * 8), 8);
        ecc_bytes = ALIGN(ecc_bytes, 2);

        return ecc_bytes;
}

NAND_ECC_CAPS_SINGLE(meson_gxl_ecc_caps,
                     meson_nand_calc_ecc_bytes, 1024, 8, 24, 30, 40, 50, 60);

static const int axg_stepinfo_strengths[] = { 8 };

static const struct nand_ecc_step_info axg_stepinfo[] = {
        {
                .stepsize = 1024,
                .strengths = axg_stepinfo_strengths,
                .nstrengths = ARRAY_SIZE(axg_stepinfo_strengths)
        },
        {
                .stepsize = 512,
                .strengths = axg_stepinfo_strengths,
                .nstrengths = ARRAY_SIZE(axg_stepinfo_strengths)
        },
};

static const struct nand_ecc_caps meson_axg_ecc_caps = {
        .stepinfos = axg_stepinfo,
        .nstepinfos = ARRAY_SIZE(axg_stepinfo),
        .calc_ecc_bytes = meson_nand_calc_ecc_bytes,
};

static struct meson_nfc_nand_chip *to_meson_nand(struct nand_chip *nand)
{
        return container_of(nand, struct meson_nfc_nand_chip, nand);
}

static void meson_nfc_select_chip(struct nand_chip *nand, int chip)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        int ret, value;

        if (chip < 0 || WARN_ON_ONCE(chip >= meson_chip->nsels))
                return;

        nfc->param.chip_select = meson_chip->sels[chip] ? NAND_CE1 : NAND_CE0;
        nfc->param.rb_select = nfc->param.chip_select;
        nfc->timing.twb = meson_chip->twb;
        nfc->timing.tadl = meson_chip->tadl;
        nfc->timing.tbers_max = meson_chip->tbers_max;

        if (nfc->clk_rate != meson_chip->clk_rate) {
                ret = clk_set_rate(nfc->nand_clk, meson_chip->clk_rate);
                if (ret) {
                        dev_err(nfc->dev, "failed to set clock rate\n");
                        return;
                }
                nfc->clk_rate = meson_chip->clk_rate;
        }
        if (nfc->bus_timing != meson_chip->bus_timing) {
                value = (NFC_CLK_CYCLE - 1) | (meson_chip->bus_timing << 5);
                writel(value, nfc->reg_base + NFC_REG_CFG);
                writel((1 << 31), nfc->reg_base + NFC_REG_CMD);
                nfc->bus_timing =  meson_chip->bus_timing;
        }
}

static void meson_nfc_cmd_idle(struct meson_nfc *nfc, u32 time)
{
        writel(nfc->param.chip_select | NFC_CMD_IDLE | (time & 0x3ff),
               nfc->reg_base + NFC_REG_CMD);
}

static void meson_nfc_cmd_seed(struct meson_nfc *nfc, u32 seed)
{
        writel(NFC_CMD_SEED | (0xc2 + (seed & 0x7fff)),
               nfc->reg_base + NFC_REG_CMD);
}

static int meson_nfc_is_boot_page(struct nand_chip *nand, int page)
{
        const struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);

        return (nand->options & NAND_IS_BOOT_MEDIUM) &&
               !(page % meson_chip->boot_page_step) &&
               (page < meson_chip->boot_pages);
}

static void meson_nfc_cmd_access(struct nand_chip *nand, int raw, bool dir, int page)
{
        const struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        struct mtd_info *mtd = nand_to_mtd(nand);
        struct meson_nfc *nfc = nand_get_controller_data(mtd_to_nand(mtd));
        int len = mtd->writesize, pagesize, pages;
        int scrambler;
        u32 cmd;

        if (nand->options & NAND_NEED_SCRAMBLING)
                scrambler = NFC_CMD_SCRAMBLER_ENABLE;
        else
                scrambler = NFC_CMD_SCRAMBLER_DISABLE;

        if (raw) {
                len = mtd->writesize + mtd->oobsize;
                cmd = len | scrambler | DMA_DIR(dir);
        } else if (meson_nfc_is_boot_page(nand, page)) {
                pagesize = NFC_SHORT_MODE_ECC_SZ >> 3;
                pages = mtd->writesize / 512;

                scrambler = NFC_CMD_SCRAMBLER_ENABLE;
                cmd = CMDRWGEN(DMA_DIR(dir), scrambler, NFC_ECC_BCH8_1K,
                               NFC_CMD_SHORTMODE_ENABLE, pagesize, pages);
        } else {
                pagesize = nand->ecc.size >> 3;
                pages = len / nand->ecc.size;

                cmd = CMDRWGEN(DMA_DIR(dir), scrambler, meson_chip->bch_mode,
                               NFC_CMD_SHORTMODE_DISABLE, pagesize, pages);
        }

        if (scrambler == NFC_CMD_SCRAMBLER_ENABLE)
                meson_nfc_cmd_seed(nfc, page);

        writel(cmd, nfc->reg_base + NFC_REG_CMD);
}

static void meson_nfc_drain_cmd(struct meson_nfc *nfc)
{
        /*
         * Insert two commands to make sure all valid commands are finished.
         *
         * The Nand flash controller is designed as two stages pipleline -
         *  a) fetch and b) excute.
         * There might be cases when the driver see command queue is empty,
         * but the Nand flash controller still has two commands buffered,
         * one is fetched into NFC request queue (ready to run), and another
         * is actively executing. So pushing 2 "IDLE" commands guarantees that
         * the pipeline is emptied.
         */
        meson_nfc_cmd_idle(nfc, 0);
        meson_nfc_cmd_idle(nfc, 0);
}

static int meson_nfc_wait_cmd_finish(struct meson_nfc *nfc,
                                     unsigned int timeout_ms)
{
        u32 cmd_size = 0;
        int ret;

        /* wait cmd fifo is empty */
        ret = readl_relaxed_poll_timeout(nfc->reg_base + NFC_REG_CMD, cmd_size,
                                         !NFC_CMD_GET_SIZE(cmd_size),
                                         10, timeout_ms * 1000);
        if (ret)
                dev_err(nfc->dev, "wait for empty CMD FIFO time out\n");

        return ret;
}

static int meson_nfc_wait_dma_finish(struct meson_nfc *nfc)
{
        meson_nfc_drain_cmd(nfc);

        return meson_nfc_wait_cmd_finish(nfc, DMA_BUSY_TIMEOUT);
}

static u8 *meson_nfc_oob_ptr(struct nand_chip *nand, int i)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        int len;

        len = nand->ecc.size * (i + 1) + (nand->ecc.bytes + 2) * i;

        return meson_chip->data_buf + len;
}

static u8 *meson_nfc_data_ptr(struct nand_chip *nand, int i)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        int len, temp;

        temp = nand->ecc.size + nand->ecc.bytes;
        len = (temp + 2) * i;

        return meson_chip->data_buf + len;
}

static void meson_nfc_get_data_oob(struct nand_chip *nand,
                                   u8 *buf, u8 *oobbuf)
{
        int i, oob_len = 0;
        u8 *dsrc, *osrc;

        oob_len = nand->ecc.bytes + 2;
        for (i = 0; i < nand->ecc.steps; i++) {
                if (buf) {
                        dsrc = meson_nfc_data_ptr(nand, i);
                        memcpy(buf, dsrc, nand->ecc.size);
                        buf += nand->ecc.size;
                }
                osrc = meson_nfc_oob_ptr(nand, i);
                memcpy(oobbuf, osrc, oob_len);
                oobbuf += oob_len;
        }
}

static void meson_nfc_set_data_oob(struct nand_chip *nand,
                                   const u8 *buf, u8 *oobbuf)
{
        int i, oob_len = 0;
        u8 *dsrc, *osrc;

        oob_len = nand->ecc.bytes + 2;
        for (i = 0; i < nand->ecc.steps; i++) {
                if (buf) {
                        dsrc = meson_nfc_data_ptr(nand, i);
                        memcpy(dsrc, buf, nand->ecc.size);
                        buf += nand->ecc.size;
                }
                osrc = meson_nfc_oob_ptr(nand, i);
                memcpy(osrc, oobbuf, oob_len);
                oobbuf += oob_len;
        }
}

static int meson_nfc_wait_no_rb_pin(struct nand_chip *nand, int timeout_ms,
                                    bool need_cmd_read0)
{
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        u32 cmd, cfg;

        meson_nfc_cmd_idle(nfc, nfc->timing.twb);
        meson_nfc_drain_cmd(nfc);
        meson_nfc_wait_cmd_finish(nfc, CMD_FIFO_EMPTY_TIMEOUT);

        cfg = readl(nfc->reg_base + NFC_REG_CFG);
        cfg |= NFC_RB_IRQ_EN;
        writel(cfg, nfc->reg_base + NFC_REG_CFG);

        reinit_completion(&nfc->completion);
        nand_status_op(nand, NULL);

        /* use the max erase time as the maximum clock for waiting R/B */
        cmd = NFC_CMD_RB | NFC_CMD_RB_INT_NO_PIN | nfc->timing.tbers_max;
        writel(cmd, nfc->reg_base + NFC_REG_CMD);

        if (!wait_for_completion_timeout(&nfc->completion,
                                         msecs_to_jiffies(timeout_ms)))
                return -ETIMEDOUT;

        if (need_cmd_read0)
                nand_exit_status_op(nand);

        return 0;
}

static int meson_nfc_wait_rb_pin(struct meson_nfc *nfc, int timeout_ms)
{
        u32 cmd, cfg;
        int ret = 0;

        meson_nfc_cmd_idle(nfc, nfc->timing.twb);
        meson_nfc_drain_cmd(nfc);
        meson_nfc_wait_cmd_finish(nfc, CMD_FIFO_EMPTY_TIMEOUT);

        cfg = readl(nfc->reg_base + NFC_REG_CFG);
        cfg |= NFC_RB_IRQ_EN;
        writel(cfg, nfc->reg_base + NFC_REG_CFG);

        reinit_completion(&nfc->completion);

        /* use the max erase time as the maximum clock for waiting R/B */
        cmd = NFC_CMD_RB | NFC_CMD_RB_INT
                | nfc->param.chip_select | nfc->timing.tbers_max;
        writel(cmd, nfc->reg_base + NFC_REG_CMD);

        ret = wait_for_completion_timeout(&nfc->completion,
                                          msecs_to_jiffies(timeout_ms));
        if (ret == 0)
                ret = -1;

        return ret;
}

static int meson_nfc_queue_rb(struct nand_chip *nand, int timeout_ms,
                              bool need_cmd_read0)
{
        struct meson_nfc *nfc = nand_get_controller_data(nand);

        if (nfc->no_rb_pin) {
                /* This mode is used when there is no wired R/B pin.
                 * It works like 'nand_soft_waitrdy()', but instead of
                 * polling NAND_CMD_STATUS bit in the software loop,
                 * it will wait for interrupt - controllers checks IO
                 * bus and when it detects NAND_CMD_STATUS on it, it
                 * raises interrupt. After interrupt, NAND_CMD_READ0 is
                 * sent as terminator of the ready waiting procedure if
                 * needed (for all cases except page programming - this
                 * is reason of 'need_cmd_read0' flag).
                 */
                return meson_nfc_wait_no_rb_pin(nand, timeout_ms,
                                                need_cmd_read0);
        } else {
                return meson_nfc_wait_rb_pin(nfc, timeout_ms);
        }
}

static void meson_nfc_set_user_byte(struct nand_chip *nand, u8 *oob_buf)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        __le64 *info;
        int i, count;

        for (i = 0, count = 0; i < nand->ecc.steps; i++, count += (2 + nand->ecc.bytes)) {
                info = &meson_chip->info_buf[i];
                *info |= oob_buf[count];
                *info |= oob_buf[count + 1] << 8;
        }
}

static void meson_nfc_get_user_byte(struct nand_chip *nand, u8 *oob_buf)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        __le64 *info;
        int i, count;

        for (i = 0, count = 0; i < nand->ecc.steps; i++, count += (2 + nand->ecc.bytes)) {
                info = &meson_chip->info_buf[i];
                oob_buf[count] = *info;
                oob_buf[count + 1] = *info >> 8;
        }
}

static int meson_nfc_ecc_correct(struct nand_chip *nand, u32 *bitflips,
                                 u64 *correct_bitmap)
{
        struct mtd_info *mtd = nand_to_mtd(nand);
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        __le64 *info;
        int ret = 0, i;

        for (i = 0; i < nand->ecc.steps; i++) {
                info = &meson_chip->info_buf[i];
                if (ECC_ERR_CNT(*info) != ECC_UNCORRECTABLE) {
                        mtd->ecc_stats.corrected += ECC_ERR_CNT(*info);
                        *bitflips = max_t(u32, *bitflips, ECC_ERR_CNT(*info));
                        *correct_bitmap |= BIT_ULL(i);
                        continue;
                }
                if ((nand->options & NAND_NEED_SCRAMBLING) &&
                    ECC_ZERO_CNT(*info) < nand->ecc.strength) {
                        mtd->ecc_stats.corrected += ECC_ZERO_CNT(*info);
                        *bitflips = max_t(u32, *bitflips,
                                          ECC_ZERO_CNT(*info));
                        ret = ECC_CHECK_RETURN_FF;
                } else {
                        ret = -EBADMSG;
                }
        }
        return ret;
}

static int meson_nfc_dma_buffer_setup(struct nand_chip *nand, void *databuf,
                                      int datalen, void *infobuf, int infolen,
                                      enum dma_data_direction dir)
{
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        u32 cmd;
        int ret = 0;

        nfc->daddr = dma_map_single(nfc->dev, databuf, datalen, dir);
        ret = dma_mapping_error(nfc->dev, nfc->daddr);
        if (ret) {
                dev_err(nfc->dev, "DMA mapping error\n");
                return ret;
        }
        cmd = GENCMDDADDRL(NFC_CMD_ADL, nfc->daddr);
        writel(cmd, nfc->reg_base + NFC_REG_CMD);

        cmd = GENCMDDADDRH(NFC_CMD_ADH, nfc->daddr);
        writel(cmd, nfc->reg_base + NFC_REG_CMD);

        if (infobuf) {
                nfc->iaddr = dma_map_single(nfc->dev, infobuf, infolen, dir);
                ret = dma_mapping_error(nfc->dev, nfc->iaddr);
                if (ret) {
                        dev_err(nfc->dev, "DMA mapping error\n");
                        dma_unmap_single(nfc->dev,
                                         nfc->daddr, datalen, dir);
                        return ret;
                }
                nfc->info_bytes = infolen;
                cmd = GENCMDIADDRL(NFC_CMD_AIL, nfc->iaddr);
                writel(cmd, nfc->reg_base + NFC_REG_CMD);

                cmd = GENCMDIADDRH(NFC_CMD_AIH, nfc->iaddr);
                writel(cmd, nfc->reg_base + NFC_REG_CMD);
        }

        return ret;
}

static void meson_nfc_dma_buffer_release(struct nand_chip *nand,
                                         int datalen, int infolen,
                                         enum dma_data_direction dir)
{
        struct meson_nfc *nfc = nand_get_controller_data(nand);

        dma_unmap_single(nfc->dev, nfc->daddr, datalen, dir);
        if (infolen) {
                dma_unmap_single(nfc->dev, nfc->iaddr, infolen, dir);
                nfc->info_bytes = 0;
        }
}

static int meson_nfc_read_buf(struct nand_chip *nand, u8 *buf, int len)
{
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        int ret = 0;
        u32 cmd;
        u8 *info;

        info = kzalloc(PER_INFO_BYTE, GFP_KERNEL);
        if (!info)
                return -ENOMEM;

        ret = meson_nfc_dma_buffer_setup(nand, buf, len, info,
                                         PER_INFO_BYTE, DMA_FROM_DEVICE);
        if (ret)
                goto out;

        cmd = NFC_CMD_N2M | len;
        writel(cmd, nfc->reg_base + NFC_REG_CMD);

        meson_nfc_drain_cmd(nfc);
        meson_nfc_wait_cmd_finish(nfc, 1000);
        meson_nfc_dma_buffer_release(nand, len, PER_INFO_BYTE, DMA_FROM_DEVICE);

out:
        kfree(info);

        return ret;
}

static int meson_nfc_write_buf(struct nand_chip *nand, u8 *buf, int len)
{
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        int ret = 0;
        u32 cmd;

        ret = meson_nfc_dma_buffer_setup(nand, buf, len, NULL,
                                         0, DMA_TO_DEVICE);
        if (ret)
                return ret;

        cmd = NFC_CMD_M2N | len;
        writel(cmd, nfc->reg_base + NFC_REG_CMD);

        meson_nfc_drain_cmd(nfc);
        meson_nfc_wait_cmd_finish(nfc, 1000);
        meson_nfc_dma_buffer_release(nand, len, 0, DMA_TO_DEVICE);

        return ret;
}

static int meson_nfc_rw_cmd_prepare_and_execute(struct nand_chip *nand,
                                                int page, bool in)
{
        const struct nand_sdr_timings *sdr =
                nand_get_sdr_timings(nand_get_interface_config(nand));
        struct mtd_info *mtd = nand_to_mtd(nand);
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        u32 *addrs = nfc->cmdfifo.rw.addrs;
        u32 cs = nfc->param.chip_select;
        u32 cmd0, cmd_num, row_start;
        int i;

        cmd_num = sizeof(struct nand_rw_cmd) / sizeof(int);

        cmd0 = in ? NAND_CMD_READ0 : NAND_CMD_SEQIN;
        nfc->cmdfifo.rw.cmd0 = cs | NFC_CMD_CLE | cmd0;

        addrs[0] = cs | NFC_CMD_ALE | NFC_COLUMN_ADDR_0;
        if (mtd->writesize <= 512) {
                cmd_num--;
                row_start = 1;
        } else {
                addrs[1] = cs | NFC_CMD_ALE | NFC_COLUMN_ADDR_1;
                row_start = 2;
        }

        addrs[row_start] = cs | NFC_CMD_ALE | ROW_ADDER(page, 0);
        addrs[row_start + 1] = cs | NFC_CMD_ALE | ROW_ADDER(page, 1);

        if (nand->options & NAND_ROW_ADDR_3)
                addrs[row_start + 2] =
                        cs | NFC_CMD_ALE | ROW_ADDER(page, 2);
        else
                cmd_num--;

        /* subtract cmd1 */
        cmd_num--;

        for (i = 0; i < cmd_num; i++)
                writel_relaxed(nfc->cmdfifo.cmd[i],
                               nfc->reg_base + NFC_REG_CMD);

        if (in) {
                nfc->cmdfifo.rw.cmd1 = cs | NFC_CMD_CLE | NAND_CMD_READSTART;
                writel(nfc->cmdfifo.rw.cmd1, nfc->reg_base + NFC_REG_CMD);
                meson_nfc_queue_rb(nand, PSEC_TO_MSEC(sdr->tR_max), true);
        } else {
                meson_nfc_cmd_idle(nfc, nfc->timing.tadl);
        }

        return 0;
}

static int meson_nfc_write_page_sub(struct nand_chip *nand,
                                    int page, int raw)
{
        const struct nand_sdr_timings *sdr =
                nand_get_sdr_timings(nand_get_interface_config(nand));
        struct mtd_info *mtd = nand_to_mtd(nand);
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        int data_len, info_len;
        u32 cmd;
        int ret;

        meson_nfc_select_chip(nand, nand->cur_cs);

        data_len =  mtd->writesize + mtd->oobsize;
        info_len = nand->ecc.steps * PER_INFO_BYTE;

        ret = meson_nfc_rw_cmd_prepare_and_execute(nand, page, DIRWRITE);
        if (ret)
                return ret;

        ret = meson_nfc_dma_buffer_setup(nand, meson_chip->data_buf,
                                         data_len, meson_chip->info_buf,
                                         info_len, DMA_TO_DEVICE);
        if (ret)
                return ret;

        meson_nfc_cmd_access(nand, raw, DIRWRITE, page);

        cmd = nfc->param.chip_select | NFC_CMD_CLE | NAND_CMD_PAGEPROG;
        writel(cmd, nfc->reg_base + NFC_REG_CMD);
        meson_nfc_queue_rb(nand, PSEC_TO_MSEC(sdr->tPROG_max), false);

        meson_nfc_dma_buffer_release(nand, data_len, info_len, DMA_TO_DEVICE);

        return ret;
}

static int meson_nfc_write_page_raw(struct nand_chip *nand, const u8 *buf,
                                    int oob_required, int page)
{
        u8 *oob_buf = nand->oob_poi;

        meson_nfc_set_data_oob(nand, buf, oob_buf);

        return meson_nfc_write_page_sub(nand, page, 1);
}

static int meson_nfc_write_page_hwecc(struct nand_chip *nand,
                                      const u8 *buf, int oob_required, int page)
{
        struct mtd_info *mtd = nand_to_mtd(nand);
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        u8 *oob_buf = nand->oob_poi;

        memcpy(meson_chip->data_buf, buf, mtd->writesize);
        memset(meson_chip->info_buf, 0, nand->ecc.steps * PER_INFO_BYTE);
        meson_nfc_set_user_byte(nand, oob_buf);

        return meson_nfc_write_page_sub(nand, page, 0);
}

static void meson_nfc_check_ecc_pages_valid(struct meson_nfc *nfc,
                                            struct nand_chip *nand, int raw)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        __le64 *info;
        u32 neccpages;
        int ret;

        neccpages = raw ? 1 : nand->ecc.steps;
        info = &meson_chip->info_buf[neccpages - 1];
        do {
                usleep_range(10, 15);
                /* info is updated by nfc dma engine*/
                smp_rmb();
                dma_sync_single_for_cpu(nfc->dev, nfc->iaddr, nfc->info_bytes,
                                        DMA_FROM_DEVICE);
                ret = *info & ECC_COMPLETE;
        } while (!ret);
}

static int meson_nfc_read_page_sub(struct nand_chip *nand,
                                   int page, int raw)
{
        struct mtd_info *mtd = nand_to_mtd(nand);
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        int data_len, info_len;
        int ret;

        meson_nfc_select_chip(nand, nand->cur_cs);

        data_len =  mtd->writesize + mtd->oobsize;
        info_len = nand->ecc.steps * PER_INFO_BYTE;

        ret = meson_nfc_rw_cmd_prepare_and_execute(nand, page, DIRREAD);
        if (ret)
                return ret;

        ret = meson_nfc_dma_buffer_setup(nand, meson_chip->data_buf,
                                         data_len, meson_chip->info_buf,
                                         info_len, DMA_FROM_DEVICE);
        if (ret)
                return ret;

        meson_nfc_cmd_access(nand, raw, DIRREAD, page);

        ret = meson_nfc_wait_dma_finish(nfc);
        meson_nfc_check_ecc_pages_valid(nfc, nand, raw);

        meson_nfc_dma_buffer_release(nand, data_len, info_len, DMA_FROM_DEVICE);

        return ret;
}

static int meson_nfc_read_page_raw(struct nand_chip *nand, u8 *buf,
                                   int oob_required, int page)
{
        u8 *oob_buf = nand->oob_poi;
        int ret;

        ret = meson_nfc_read_page_sub(nand, page, 1);
        if (ret)
                return ret;

        meson_nfc_get_data_oob(nand, buf, oob_buf);

        return 0;
}

static int meson_nfc_read_page_hwecc(struct nand_chip *nand, u8 *buf,
                                     int oob_required, int page)
{
        struct mtd_info *mtd = nand_to_mtd(nand);
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        struct nand_ecc_ctrl *ecc = &nand->ecc;
        u64 correct_bitmap = 0;
        u32 bitflips = 0;
        u8 *oob_buf = nand->oob_poi;
        int ret, i;

        ret = meson_nfc_read_page_sub(nand, page, 0);
        if (ret)
                return ret;

        meson_nfc_get_user_byte(nand, oob_buf);
        ret = meson_nfc_ecc_correct(nand, &bitflips, &correct_bitmap);
        if (ret == ECC_CHECK_RETURN_FF) {
                if (buf)
                        memset(buf, 0xff, mtd->writesize);
                memset(oob_buf, 0xff, mtd->oobsize);
        } else if (ret < 0) {
                if ((nand->options & NAND_NEED_SCRAMBLING) || !buf) {
                        mtd->ecc_stats.failed++;
                        return bitflips;
                }
                ret  = meson_nfc_read_page_raw(nand, buf, 0, page);
                if (ret)
                        return ret;

                for (i = 0; i < nand->ecc.steps ; i++) {
                        u8 *data = buf + i * ecc->size;
                        u8 *oob = nand->oob_poi + i * (ecc->bytes + 2);

                        if (correct_bitmap & BIT_ULL(i))
                                continue;
                        ret = nand_check_erased_ecc_chunk(data, ecc->size,
                                                          oob, ecc->bytes + 2,
                                                          NULL, 0,
                                                          ecc->strength);
                        if (ret < 0) {
                                mtd->ecc_stats.failed++;
                        } else {
                                mtd->ecc_stats.corrected += ret;
                                bitflips =  max_t(u32, bitflips, ret);
                        }
                }
        } else if (buf && buf != meson_chip->data_buf) {
                memcpy(buf, meson_chip->data_buf, mtd->writesize);
        }

        return bitflips;
}

static int meson_nfc_read_oob_raw(struct nand_chip *nand, int page)
{
        return meson_nfc_read_page_raw(nand, NULL, 1, page);
}

static int meson_nfc_read_oob(struct nand_chip *nand, int page)
{
        return meson_nfc_read_page_hwecc(nand, NULL, 1, page);
}

static bool meson_nfc_is_buffer_dma_safe(const void *buffer)
{
        if ((uintptr_t)buffer % DMA_ADDR_ALIGN)
                return false;

        if (virt_addr_valid(buffer) && (!object_is_on_stack(buffer)))
                return true;
        return false;
}

static void *
meson_nand_op_get_dma_safe_input_buf(const struct nand_op_instr *instr)
{
        if (WARN_ON(instr->type != NAND_OP_DATA_IN_INSTR))
                return NULL;

        if (meson_nfc_is_buffer_dma_safe(instr->ctx.data.buf.in))
                return instr->ctx.data.buf.in;

        return kzalloc(instr->ctx.data.len, GFP_KERNEL);
}

static void
meson_nand_op_put_dma_safe_input_buf(const struct nand_op_instr *instr,
                                     void *buf)
{
        if (WARN_ON(instr->type != NAND_OP_DATA_IN_INSTR) ||
            WARN_ON(!buf))
                return;

        if (buf == instr->ctx.data.buf.in)
                return;

        memcpy(instr->ctx.data.buf.in, buf, instr->ctx.data.len);
        kfree(buf);
}

static void *
meson_nand_op_get_dma_safe_output_buf(const struct nand_op_instr *instr)
{
        if (WARN_ON(instr->type != NAND_OP_DATA_OUT_INSTR))
                return NULL;

        if (meson_nfc_is_buffer_dma_safe(instr->ctx.data.buf.out))
                return (void *)instr->ctx.data.buf.out;

        return kmemdup(instr->ctx.data.buf.out,
                       instr->ctx.data.len, GFP_KERNEL);
}

static void
meson_nand_op_put_dma_safe_output_buf(const struct nand_op_instr *instr,
                                      const void *buf)
{
        if (WARN_ON(instr->type != NAND_OP_DATA_OUT_INSTR) ||
            WARN_ON(!buf))
                return;

        if (buf != instr->ctx.data.buf.out)
                kfree(buf);
}

static int meson_nfc_check_op(struct nand_chip *chip,
                              const struct nand_operation *op)
{
        int op_id;

        for (op_id = 0; op_id < op->ninstrs; op_id++) {
                const struct nand_op_instr *instr;

                instr = &op->instrs[op_id];

                switch (instr->type) {
                case NAND_OP_DATA_IN_INSTR:
                case NAND_OP_DATA_OUT_INSTR:
                        if (instr->ctx.data.len > NFC_CMD_RAW_LEN)
                                return -ENOTSUPP;

                        break;
                default:
                        break;
                }
        }

        return 0;
}

static int meson_nfc_exec_op(struct nand_chip *nand,
                             const struct nand_operation *op, bool check_only)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        const struct nand_op_instr *instr = NULL;
        void *buf;
        u32 op_id, delay_idle, cmd;
        int err;
        int i;

        err = meson_nfc_check_op(nand, op);
        if (err)
                return err;

        if (check_only)
                return 0;

        meson_nfc_select_chip(nand, op->cs);
        for (op_id = 0; op_id < op->ninstrs; op_id++) {
                instr = &op->instrs[op_id];
                delay_idle = DIV_ROUND_UP(PSEC_TO_NSEC(instr->delay_ns),
                                          meson_chip->level1_divider *
                                          NFC_CLK_CYCLE);
                switch (instr->type) {
                case NAND_OP_CMD_INSTR:
                        cmd = nfc->param.chip_select | NFC_CMD_CLE;
                        cmd |= instr->ctx.cmd.opcode & 0xff;
                        writel(cmd, nfc->reg_base + NFC_REG_CMD);
                        meson_nfc_cmd_idle(nfc, delay_idle);
                        break;

                case NAND_OP_ADDR_INSTR:
                        for (i = 0; i < instr->ctx.addr.naddrs; i++) {
                                cmd = nfc->param.chip_select | NFC_CMD_ALE;
                                cmd |= instr->ctx.addr.addrs[i] & 0xff;
                                writel(cmd, nfc->reg_base + NFC_REG_CMD);
                        }
                        meson_nfc_cmd_idle(nfc, delay_idle);
                        break;

                case NAND_OP_DATA_IN_INSTR:
                        buf = meson_nand_op_get_dma_safe_input_buf(instr);
                        if (!buf)
                                return -ENOMEM;
                        meson_nfc_read_buf(nand, buf, instr->ctx.data.len);
                        meson_nand_op_put_dma_safe_input_buf(instr, buf);
                        break;

                case NAND_OP_DATA_OUT_INSTR:
                        buf = meson_nand_op_get_dma_safe_output_buf(instr);
                        if (!buf)
                                return -ENOMEM;
                        meson_nfc_write_buf(nand, buf, instr->ctx.data.len);
                        meson_nand_op_put_dma_safe_output_buf(instr, buf);
                        break;

                case NAND_OP_WAITRDY_INSTR:
                        meson_nfc_queue_rb(nand, instr->ctx.waitrdy.timeout_ms,
                                           true);
                        if (instr->delay_ns)
                                meson_nfc_cmd_idle(nfc, delay_idle);
                        break;
                }
        }
        meson_nfc_wait_cmd_finish(nfc, 1000);
        return 0;
}

static int meson_ooblayout_ecc(struct mtd_info *mtd, int section,
                               struct mtd_oob_region *oobregion)
{
        struct nand_chip *nand = mtd_to_nand(mtd);

        if (section >= nand->ecc.steps)
                return -ERANGE;

        oobregion->offset =  2 + (section * (2 + nand->ecc.bytes));
        oobregion->length = nand->ecc.bytes;

        return 0;
}

static int meson_ooblayout_free(struct mtd_info *mtd, int section,
                                struct mtd_oob_region *oobregion)
{
        struct nand_chip *nand = mtd_to_nand(mtd);

        if (section >= nand->ecc.steps)
                return -ERANGE;

        oobregion->offset = section * (2 + nand->ecc.bytes);
        oobregion->length = 2;

        return 0;
}

static const struct mtd_ooblayout_ops meson_ooblayout_ops = {
        .ecc = meson_ooblayout_ecc,
        .free = meson_ooblayout_free,
};

static int meson_nfc_clk_init(struct meson_nfc *nfc)
{
        struct clk_parent_data nfc_divider_parent_data[1] = {0};
        struct clk_init_data init = {0};
        int ret;

        /* request core clock */
        nfc->core_clk = devm_clk_get(nfc->dev, "core");
        if (IS_ERR(nfc->core_clk)) {
                dev_err(nfc->dev, "failed to get core clock\n");
                return PTR_ERR(nfc->core_clk);
        }

        nfc->device_clk = devm_clk_get(nfc->dev, "device");
        if (IS_ERR(nfc->device_clk)) {
                dev_err(nfc->dev, "failed to get device clock\n");
                return PTR_ERR(nfc->device_clk);
        }

        init.name = devm_kasprintf(nfc->dev,
                                   GFP_KERNEL, "%s#div",
                                   dev_name(nfc->dev));
        if (!init.name)
                return -ENOMEM;

        init.ops = &clk_divider_ops;
        nfc_divider_parent_data[0].fw_name = "device";
        init.parent_data = nfc_divider_parent_data;
        init.num_parents = 1;
        nfc->nand_divider.reg = nfc->reg_clk;
        nfc->nand_divider.shift = CLK_DIV_SHIFT;
        nfc->nand_divider.width = CLK_DIV_WIDTH;
        nfc->nand_divider.hw.init = &init;
        nfc->nand_divider.flags = CLK_DIVIDER_ONE_BASED |
                                  CLK_DIVIDER_ROUND_CLOSEST |
                                  CLK_DIVIDER_ALLOW_ZERO;

        nfc->nand_clk = devm_clk_register(nfc->dev, &nfc->nand_divider.hw);
        if (IS_ERR(nfc->nand_clk))
                return PTR_ERR(nfc->nand_clk);

        /* init SD_EMMC_CLOCK to sane defaults w/min clock rate */
        writel(CLK_ALWAYS_ON_NAND | CLK_SELECT_NAND | CLK_SELECT_FIX_PLL2,
               nfc->reg_clk);

        ret = clk_prepare_enable(nfc->core_clk);
        if (ret) {
                dev_err(nfc->dev, "failed to enable core clock\n");
                return ret;
        }

        ret = clk_prepare_enable(nfc->device_clk);
        if (ret) {
                dev_err(nfc->dev, "failed to enable device clock\n");
                goto err_device_clk;
        }

        ret = clk_prepare_enable(nfc->nand_clk);
        if (ret) {
                dev_err(nfc->dev, "pre enable NFC divider fail\n");
                goto err_nand_clk;
        }

        ret = clk_set_rate(nfc->nand_clk, 24000000);
        if (ret)
                goto err_disable_clk;

        return 0;

err_disable_clk:
        clk_disable_unprepare(nfc->nand_clk);
err_nand_clk:
        clk_disable_unprepare(nfc->device_clk);
err_device_clk:
        clk_disable_unprepare(nfc->core_clk);
        return ret;
}

static void meson_nfc_disable_clk(struct meson_nfc *nfc)
{
        clk_disable_unprepare(nfc->nand_clk);
        clk_disable_unprepare(nfc->device_clk);
        clk_disable_unprepare(nfc->core_clk);
}

static void meson_nfc_free_buffer(struct nand_chip *nand)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);

        kfree(meson_chip->info_buf);
        kfree(meson_chip->data_buf);
}

static int meson_chip_buffer_init(struct nand_chip *nand)
{
        struct mtd_info *mtd = nand_to_mtd(nand);
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        u32 page_bytes, info_bytes, nsectors;

        nsectors = mtd->writesize / nand->ecc.size;

        page_bytes =  mtd->writesize + mtd->oobsize;
        info_bytes = nsectors * PER_INFO_BYTE;

        meson_chip->data_buf = kmalloc(page_bytes, GFP_KERNEL);
        if (!meson_chip->data_buf)
                return -ENOMEM;

        meson_chip->info_buf = kmalloc(info_bytes, GFP_KERNEL);
        if (!meson_chip->info_buf) {
                kfree(meson_chip->data_buf);
                return -ENOMEM;
        }

        return 0;
}

static
int meson_nfc_setup_interface(struct nand_chip *nand, int csline,
                              const struct nand_interface_config *conf)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        const struct nand_sdr_timings *timings;
        u32 div, bt_min, bt_max, tbers_clocks;

        timings = nand_get_sdr_timings(conf);
        if (IS_ERR(timings))
                return -ENOTSUPP;

        if (csline == NAND_DATA_IFACE_CHECK_ONLY)
                return 0;

        div = DIV_ROUND_UP((timings->tRC_min / 1000), NFC_CLK_CYCLE);
        bt_min = (timings->tREA_max + NFC_DEFAULT_DELAY) / div;
        bt_max = (NFC_DEFAULT_DELAY + timings->tRHOH_min +
                  timings->tRC_min / 2) / div;

        meson_chip->twb = DIV_ROUND_UP(PSEC_TO_NSEC(timings->tWB_max),
                                       div * NFC_CLK_CYCLE);
        meson_chip->tadl = DIV_ROUND_UP(PSEC_TO_NSEC(timings->tADL_min),
                                        div * NFC_CLK_CYCLE);
        tbers_clocks = DIV_ROUND_UP_ULL(PSEC_TO_NSEC(timings->tBERS_max),
                                        div * NFC_CLK_CYCLE);
        meson_chip->tbers_max = ilog2(tbers_clocks);
        if (!is_power_of_2(tbers_clocks))
                meson_chip->tbers_max++;

        bt_min = DIV_ROUND_UP(bt_min, 1000);
        bt_max = DIV_ROUND_UP(bt_max, 1000);

        if (bt_max < bt_min)
                return -EINVAL;

        meson_chip->level1_divider = div;
        meson_chip->clk_rate = 1000000000 / meson_chip->level1_divider;
        meson_chip->bus_timing = (bt_min + bt_max) / 2 + 1;

        return 0;
}

static int meson_nand_bch_mode(struct nand_chip *nand)
{
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        int i;

        if (nand->ecc.strength > 60 || nand->ecc.strength < 8)
                return -EINVAL;

        for (i = 0; i < ARRAY_SIZE(meson_ecc); i++) {
                if (meson_ecc[i].strength == nand->ecc.strength &&
                    meson_ecc[i].size == nand->ecc.size) {
                        meson_chip->bch_mode = meson_ecc[i].bch;
                        return 0;
                }
        }

        return -EINVAL;
}

static void meson_nand_detach_chip(struct nand_chip *nand)
{
        meson_nfc_free_buffer(nand);
}

static int meson_nand_attach_chip(struct nand_chip *nand)
{
        struct meson_nfc *nfc = nand_get_controller_data(nand);
        struct meson_nfc_nand_chip *meson_chip = to_meson_nand(nand);
        struct mtd_info *mtd = nand_to_mtd(nand);
        int raw_writesize;
        int ret;

        if (!mtd->name) {
                mtd->name = devm_kasprintf(nfc->dev, GFP_KERNEL,
                                           "%s:nand%d",
                                           dev_name(nfc->dev),
                                           meson_chip->sels[0]);
                if (!mtd->name)
                        return -ENOMEM;
        }

        raw_writesize = mtd->writesize + mtd->oobsize;
        if (raw_writesize > NFC_CMD_RAW_LEN) {
                dev_err(nfc->dev, "too big write size in raw mode: %d > %ld\n",
                        raw_writesize, NFC_CMD_RAW_LEN);
                return -EINVAL;
        }

        if (nand->bbt_options & NAND_BBT_USE_FLASH)
                nand->bbt_options |= NAND_BBT_NO_OOB;

        nand->options |= NAND_NO_SUBPAGE_WRITE;

        ret = nand_ecc_choose_conf(nand, nfc->data->ecc_caps,
                                   mtd->oobsize - 2);
        if (ret) {
                dev_err(nfc->dev, "failed to ECC init\n");
                return -EINVAL;
        }

        mtd_set_ooblayout(mtd, &meson_ooblayout_ops);

        ret = meson_nand_bch_mode(nand);
        if (ret)
                return -EINVAL;

        nand->ecc.engine_type = NAND_ECC_ENGINE_TYPE_ON_HOST;
        nand->ecc.write_page_raw = meson_nfc_write_page_raw;
        nand->ecc.write_page = meson_nfc_write_page_hwecc;
        nand->ecc.write_oob_raw = nand_write_oob_std;
        nand->ecc.write_oob = nand_write_oob_std;

        nand->ecc.read_page_raw = meson_nfc_read_page_raw;
        nand->ecc.read_page = meson_nfc_read_page_hwecc;
        nand->ecc.read_oob_raw = meson_nfc_read_oob_raw;
        nand->ecc.read_oob = meson_nfc_read_oob;

        if (nand->options & NAND_BUSWIDTH_16) {
                dev_err(nfc->dev, "16bits bus width not supported");
                return -EINVAL;
        }
        ret = meson_chip_buffer_init(nand);
        if (ret)
                return -ENOMEM;

        return ret;
}

static const struct nand_controller_ops meson_nand_controller_ops = {
        .attach_chip = meson_nand_attach_chip,
        .detach_chip = meson_nand_detach_chip,
        .setup_interface = meson_nfc_setup_interface,
        .exec_op = meson_nfc_exec_op,
};

static int
meson_nfc_nand_chip_init(struct device *dev,
                         struct meson_nfc *nfc, struct device_node *np)
{
        struct meson_nfc_nand_chip *meson_chip;
        struct nand_chip *nand;
        struct mtd_info *mtd;
        int ret, i;
        u32 tmp, nsels;
        u32 nand_rb_val = 0;

        nsels = of_property_count_elems_of_size(np, "reg", sizeof(u32));
        if (!nsels || nsels > MAX_CE_NUM) {
                dev_err(dev, "invalid register property size\n");
                return -EINVAL;
        }

        meson_chip = devm_kzalloc(dev, struct_size(meson_chip, sels, nsels),
                                  GFP_KERNEL);
        if (!meson_chip)
                return -ENOMEM;

        meson_chip->nsels = nsels;

        for (i = 0; i < nsels; i++) {
                ret = of_property_read_u32_index(np, "reg", i, &tmp);
                if (ret) {
                        dev_err(dev, "could not retrieve register property: %d\n",
                                ret);
                        return ret;
                }

                if (test_and_set_bit(tmp, &nfc->assigned_cs)) {
                        dev_err(dev, "CS %d already assigned\n", tmp);
                        return -EINVAL;
                }
        }

        nand = &meson_chip->nand;
        nand->controller = &nfc->controller;
        nand->controller->ops = &meson_nand_controller_ops;
        nand_set_flash_node(nand, np);
        nand_set_controller_data(nand, nfc);

        nand->options |= NAND_USES_DMA;
        mtd = nand_to_mtd(nand);
        mtd->owner = THIS_MODULE;
        mtd->dev.parent = dev;

        ret = of_property_read_u32(np, "nand-rb", &nand_rb_val);
        if (ret == -EINVAL)
                nfc->no_rb_pin = true;
        else if (ret)
                return ret;

        if (nand_rb_val)
                return -EINVAL;

        ret = nand_scan(nand, nsels);
        if (ret)
                return ret;

        if (nand->options & NAND_IS_BOOT_MEDIUM) {
                ret = of_property_read_u32(np, "amlogic,boot-pages",
                                           &meson_chip->boot_pages);
                if (ret) {
                        dev_err(dev, "could not retrieve 'amlogic,boot-pages' property: %d",
                                ret);
                        nand_cleanup(nand);
                        return ret;
                }

                ret = of_property_read_u32(np, "amlogic,boot-page-step",
                                           &meson_chip->boot_page_step);
                if (ret) {
                        dev_err(dev, "could not retrieve 'amlogic,boot-page-step' property: %d",
                                ret);
                        nand_cleanup(nand);
                        return ret;
                }
        }

        ret = mtd_device_register(mtd, NULL, 0);
        if (ret) {
                dev_err(dev, "failed to register MTD device: %d\n", ret);
                nand_cleanup(nand);
                return ret;
        }

        list_add_tail(&meson_chip->node, &nfc->chips);

        return 0;
}

static void meson_nfc_nand_chips_cleanup(struct meson_nfc *nfc)
{
        struct meson_nfc_nand_chip *meson_chip;
        struct mtd_info *mtd;

        while (!list_empty(&nfc->chips)) {
                meson_chip = list_first_entry(&nfc->chips,
                                              struct meson_nfc_nand_chip, node);
                mtd = nand_to_mtd(&meson_chip->nand);
                WARN_ON(mtd_device_unregister(mtd));

                nand_cleanup(&meson_chip->nand);
                list_del(&meson_chip->node);
        }
}

static int meson_nfc_nand_chips_init(struct device *dev,
                                     struct meson_nfc *nfc)
{
        struct device_node *np = dev->of_node;
        int ret;

        for_each_child_of_node_scoped(np, nand_np) {
                ret = meson_nfc_nand_chip_init(dev, nfc, nand_np);
                if (ret) {
                        meson_nfc_nand_chips_cleanup(nfc);
                        return ret;
                }
        }

        return 0;
}

static irqreturn_t meson_nfc_irq(int irq, void *id)
{
        struct meson_nfc *nfc = id;
        u32 cfg;

        cfg = readl(nfc->reg_base + NFC_REG_CFG);
        if (!(cfg & NFC_RB_IRQ_EN))
                return IRQ_NONE;

        cfg &= ~(NFC_RB_IRQ_EN);
        writel(cfg, nfc->reg_base + NFC_REG_CFG);

        complete(&nfc->completion);
        return IRQ_HANDLED;
}

static const struct meson_nfc_data meson_gxl_data = {
        .ecc_caps = &meson_gxl_ecc_caps,
};

static const struct meson_nfc_data meson_axg_data = {
        .ecc_caps = &meson_axg_ecc_caps,
};

static const struct of_device_id meson_nfc_id_table[] = {
        {
                .compatible = "amlogic,meson-gxl-nfc",
                .data = &meson_gxl_data,
        }, {
                .compatible = "amlogic,meson-axg-nfc",
                .data = &meson_axg_data,
        },
        {}
};
MODULE_DEVICE_TABLE(of, meson_nfc_id_table);

static int meson_nfc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct meson_nfc *nfc;
        int ret, irq;

        nfc = devm_kzalloc(dev, sizeof(*nfc), GFP_KERNEL);
        if (!nfc)
                return -ENOMEM;

        nfc->data = of_device_get_match_data(&pdev->dev);
        if (!nfc->data)
                return -ENODEV;

        nand_controller_init(&nfc->controller);
        INIT_LIST_HEAD(&nfc->chips);
        init_completion(&nfc->completion);

        nfc->dev = dev;

        nfc->reg_base = devm_platform_ioremap_resource_byname(pdev, "nfc");
        if (IS_ERR(nfc->reg_base))
                return PTR_ERR(nfc->reg_base);

        nfc->reg_clk = devm_platform_ioremap_resource_byname(pdev, "emmc");
        if (IS_ERR(nfc->reg_clk))
                return PTR_ERR(nfc->reg_clk);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return -EINVAL;

        ret = meson_nfc_clk_init(nfc);
        if (ret) {
                dev_err(dev, "failed to initialize NAND clock\n");
                return ret;
        }

        writel(0, nfc->reg_base + NFC_REG_CFG);
        ret = devm_request_irq(dev, irq, meson_nfc_irq, 0, dev_name(dev), nfc);
        if (ret) {
                dev_err(dev, "failed to request NFC IRQ\n");
                ret = -EINVAL;
                goto err_clk;
        }

        ret = dma_set_mask(dev, DMA_BIT_MASK(32));
        if (ret) {
                dev_err(dev, "failed to set DMA mask\n");
                goto err_clk;
        }

        platform_set_drvdata(pdev, nfc);

        ret = meson_nfc_nand_chips_init(dev, nfc);
        if (ret) {
                dev_err(dev, "failed to init NAND chips\n");
                goto err_clk;
        }

        return 0;
err_clk:
        meson_nfc_disable_clk(nfc);
        return ret;
}

static void meson_nfc_remove(struct platform_device *pdev)
{
        struct meson_nfc *nfc = platform_get_drvdata(pdev);

        meson_nfc_nand_chips_cleanup(nfc);

        meson_nfc_disable_clk(nfc);
}

static struct platform_driver meson_nfc_driver = {
        .probe  = meson_nfc_probe,
        .remove = meson_nfc_remove,
        .driver = {
                .name  = "meson-nand",
                .of_match_table = meson_nfc_id_table,
        },
};
module_platform_driver(meson_nfc_driver);

MODULE_LICENSE("Dual MIT/GPL");
MODULE_AUTHOR("Liang Yang <liang.yang@amlogic.com>");
MODULE_DESCRIPTION("Amlogic's Meson NAND Flash Controller driver");