/*
 * Copyright 2009-2015 Freescale Semiconductor, Inc. and others
 *
 * Description: MPC5125, VF610, MCF54418 and Kinetis K70 Nand driver.
 * Jason ported to M54418TWR and MVFA5 (VF610).
 * Authors: Stefan Agner <stefan.agner@toradex.com>
 *          Bill Pringlemeir <bpringlemeir@nbsps.com>
 *          Shaohui Xie <b21989@freescale.com>
 *          Jason Jin <Jason.jin@freescale.com>
 *
 * Based on original driver mpc5121_nfc.c.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Limitations:
 * - Untested on MPC5125 and M54418.
 * - DMA and pipelining not used.
 * - 2K pages or less.
 * - HW ECC: Only 2K page with 64+ OOB.
 * - HW ECC: Only 24 and 32-bit error correction implemented.
 */

#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/partitions.h>
#include <linux/of_mtd.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#define DRV_NAME                "vf610_nfc"

/* Register Offsets */
#define NFC_FLASH_CMD1                  0x3F00
#define NFC_FLASH_CMD2                  0x3F04
#define NFC_COL_ADDR                    0x3F08
#define NFC_ROW_ADDR                    0x3F0c
#define NFC_ROW_ADDR_INC                0x3F14
#define NFC_FLASH_STATUS1               0x3F18
#define NFC_FLASH_STATUS2               0x3F1c
#define NFC_CACHE_SWAP                  0x3F28
#define NFC_SECTOR_SIZE                 0x3F2c
#define NFC_FLASH_CONFIG                0x3F30
#define NFC_IRQ_STATUS                  0x3F38

/* Addresses for NFC MAIN RAM BUFFER areas */
#define NFC_MAIN_AREA(n)                ((n) *  0x1000)

#define PAGE_2K                         0x0800
#define OOB_64                          0x0040
#define OOB_MAX                         0x0100

/*
 * NFC_CMD2[CODE] values. See section:
 *  - 31.4.7 Flash Command Code Description, Vybrid manual
 *  - 23.8.6 Flash Command Sequencer, MPC5125 manual
 *
 * Briefly these are bitmasks of controller cycles.
 */
#define READ_PAGE_CMD_CODE              0x7EE0
#define READ_ONFI_PARAM_CMD_CODE        0x4860
#define PROGRAM_PAGE_CMD_CODE           0x7FC0
#define ERASE_CMD_CODE                  0x4EC0
#define READ_ID_CMD_CODE                0x4804
#define RESET_CMD_CODE                  0x4040
#define STATUS_READ_CMD_CODE            0x4068

/* NFC ECC mode define */
#define ECC_BYPASS                      0
#define ECC_45_BYTE                     6
#define ECC_60_BYTE                     7

/*** Register Mask and bit definitions */

/* NFC_FLASH_CMD1 Field */
#define CMD_BYTE2_MASK                          0xFF000000
#define CMD_BYTE2_SHIFT                         24

/* NFC_FLASH_CM2 Field */
#define CMD_BYTE1_MASK                          0xFF000000
#define CMD_BYTE1_SHIFT                         24
#define CMD_CODE_MASK                           0x00FFFF00
#define CMD_CODE_SHIFT                          8
#define BUFNO_MASK                              0x00000006
#define BUFNO_SHIFT                             1
#define START_BIT                               BIT(0)

/* NFC_COL_ADDR Field */
#define COL_ADDR_MASK                           0x0000FFFF
#define COL_ADDR_SHIFT                          0

/* NFC_ROW_ADDR Field */
#define ROW_ADDR_MASK                           0x00FFFFFF
#define ROW_ADDR_SHIFT                          0
#define ROW_ADDR_CHIP_SEL_RB_MASK               0xF0000000
#define ROW_ADDR_CHIP_SEL_RB_SHIFT              28
#define ROW_ADDR_CHIP_SEL_MASK                  0x0F000000
#define ROW_ADDR_CHIP_SEL_SHIFT                 24

/* NFC_FLASH_STATUS2 Field */
#define STATUS_BYTE1_MASK                       0x000000FF

/* NFC_FLASH_CONFIG Field */
#define CONFIG_ECC_SRAM_ADDR_MASK               0x7FC00000
#define CONFIG_ECC_SRAM_ADDR_SHIFT              22
#define CONFIG_ECC_SRAM_REQ_BIT                 BIT(21)
#define CONFIG_DMA_REQ_BIT                      BIT(20)
#define CONFIG_ECC_MODE_MASK                    0x000E0000
#define CONFIG_ECC_MODE_SHIFT                   17
#define CONFIG_FAST_FLASH_BIT                   BIT(16)
#define CONFIG_16BIT                            BIT(7)
#define CONFIG_BOOT_MODE_BIT                    BIT(6)
#define CONFIG_ADDR_AUTO_INCR_BIT               BIT(5)
#define CONFIG_BUFNO_AUTO_INCR_BIT              BIT(4)
#define CONFIG_PAGE_CNT_MASK                    0xF
#define CONFIG_PAGE_CNT_SHIFT                   0

/* NFC_IRQ_STATUS Field */
#define IDLE_IRQ_BIT                            BIT(29)
#define IDLE_EN_BIT                             BIT(20)
#define CMD_DONE_CLEAR_BIT                      BIT(18)
#define IDLE_CLEAR_BIT                          BIT(17)

/*
 * ECC status - seems to consume 8 bytes (double word). The documented
 * status byte is located in the lowest byte of the second word (which is
 * the 4th or 7th byte depending on endianness).
 * Calculate an offset to store the ECC status at the end of the buffer.
 */
#define ECC_SRAM_ADDR           (PAGE_2K + OOB_MAX - 8)

#define ECC_STATUS              0x4
#define ECC_STATUS_MASK         0x80
#define ECC_STATUS_ERR_COUNT    0x3F

enum vf610_nfc_alt_buf {
        ALT_BUF_DATA = 0,
        ALT_BUF_ID = 1,
        ALT_BUF_STAT = 2,
        ALT_BUF_ONFI = 3,
};

enum vf610_nfc_variant {
        NFC_VFC610 = 1,
};

struct vf610_nfc {
        struct mtd_info mtd;
        struct nand_chip chip;
        struct device *dev;
        void __iomem *regs;
        struct completion cmd_done;
        uint buf_offset;
        int write_sz;
        /* Status and ID are in alternate locations. */
        enum vf610_nfc_alt_buf alt_buf;
        enum vf610_nfc_variant variant;
        struct clk *clk;
        bool use_hw_ecc;
        u32 ecc_mode;
};

#define mtd_to_nfc(_mtd) container_of(_mtd, struct vf610_nfc, mtd)

static struct nand_ecclayout vf610_nfc_ecc45 = {
        .eccbytes = 45,
        .eccpos = {19, 20, 21, 22, 23,
                   24, 25, 26, 27, 28, 29, 30, 31,
                   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 = {
                {.offset = 2,
                 .length = 17} }
};

static struct nand_ecclayout vf610_nfc_ecc60 = {
        .eccbytes = 60,
        .eccpos = { 4,  5,  6,  7,  8,  9, 10, 11,
                   12, 13, 14, 15, 16, 17, 18, 19,
                   20, 21, 22, 23, 24, 25, 26, 27,
                   28, 29, 30, 31, 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 = {
                {.offset = 2,
                 .length = 2} }
};

static inline u32 vf610_nfc_read(struct vf610_nfc *nfc, uint reg)
{
        return readl(nfc->regs + reg);
}

static inline void vf610_nfc_write(struct vf610_nfc *nfc, uint reg, u32 val)
{
        writel(val, nfc->regs + reg);
}

static inline void vf610_nfc_set(struct vf610_nfc *nfc, uint reg, u32 bits)
{
        vf610_nfc_write(nfc, reg, vf610_nfc_read(nfc, reg) | bits);
}

static inline void vf610_nfc_clear(struct vf610_nfc *nfc, uint reg, u32 bits)
{
        vf610_nfc_write(nfc, reg, vf610_nfc_read(nfc, reg) & ~bits);
}

static inline void vf610_nfc_set_field(struct vf610_nfc *nfc, u32 reg,
                                       u32 mask, u32 shift, u32 val)
{
        vf610_nfc_write(nfc, reg,
                        (vf610_nfc_read(nfc, reg) & (~mask)) | val << shift);
}

static inline void vf610_nfc_memcpy(void *dst, const void __iomem *src,
                                    size_t n)
{
        /*
         * Use this accessor for the internal SRAM buffers. On the ARM
         * Freescale Vybrid SoC it's known that the driver can treat
         * the SRAM buffer as if it's memory. Other platform might need
         * to treat the buffers differently.
         *
         * For the time being, use memcpy
         */
        memcpy(dst, src, n);
}

/* Clear flags for upcoming command */
static inline void vf610_nfc_clear_status(struct vf610_nfc *nfc)
{
        u32 tmp = vf610_nfc_read(nfc, NFC_IRQ_STATUS);

        tmp |= CMD_DONE_CLEAR_BIT | IDLE_CLEAR_BIT;
        vf610_nfc_write(nfc, NFC_IRQ_STATUS, tmp);
}

static void vf610_nfc_done(struct vf610_nfc *nfc)
{
        unsigned long timeout = msecs_to_jiffies(100);

        /*
         * Barrier is needed after this write. This write need
         * to be done before reading the next register the first
         * time.
         * vf610_nfc_set implicates such a barrier by using writel
         * to write to the register.
         */
        vf610_nfc_set(nfc, NFC_IRQ_STATUS, IDLE_EN_BIT);
        vf610_nfc_set(nfc, NFC_FLASH_CMD2, START_BIT);

        if (!wait_for_completion_timeout(&nfc->cmd_done, timeout))
                dev_warn(nfc->dev, "Timeout while waiting for BUSY.\n");

        vf610_nfc_clear_status(nfc);
}

static u8 vf610_nfc_get_id(struct vf610_nfc *nfc, int col)
{
        u32 flash_id;

        if (col < 4) {
                flash_id = vf610_nfc_read(nfc, NFC_FLASH_STATUS1);
                flash_id >>= (3 - col) * 8;
        } else {
                flash_id = vf610_nfc_read(nfc, NFC_FLASH_STATUS2);
                flash_id >>= 24;
        }

        return flash_id & 0xff;
}

static u8 vf610_nfc_get_status(struct vf610_nfc *nfc)
{
        return vf610_nfc_read(nfc, NFC_FLASH_STATUS2) & STATUS_BYTE1_MASK;
}

static void vf610_nfc_send_command(struct vf610_nfc *nfc, u32 cmd_byte1,
                                   u32 cmd_code)
{
        u32 tmp;

        vf610_nfc_clear_status(nfc);

        tmp = vf610_nfc_read(nfc, NFC_FLASH_CMD2);
        tmp &= ~(CMD_BYTE1_MASK | CMD_CODE_MASK | BUFNO_MASK);
        tmp |= cmd_byte1 << CMD_BYTE1_SHIFT;
        tmp |= cmd_code << CMD_CODE_SHIFT;
        vf610_nfc_write(nfc, NFC_FLASH_CMD2, tmp);
}

static void vf610_nfc_send_commands(struct vf610_nfc *nfc, u32 cmd_byte1,
                                    u32 cmd_byte2, u32 cmd_code)
{
        u32 tmp;

        vf610_nfc_send_command(nfc, cmd_byte1, cmd_code);

        tmp = vf610_nfc_read(nfc, NFC_FLASH_CMD1);
        tmp &= ~CMD_BYTE2_MASK;
        tmp |= cmd_byte2 << CMD_BYTE2_SHIFT;
        vf610_nfc_write(nfc, NFC_FLASH_CMD1, tmp);
}

static irqreturn_t vf610_nfc_irq(int irq, void *data)
{
        struct mtd_info *mtd = data;
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);

        vf610_nfc_clear(nfc, NFC_IRQ_STATUS, IDLE_EN_BIT);
        complete(&nfc->cmd_done);

        return IRQ_HANDLED;
}

static void vf610_nfc_addr_cycle(struct vf610_nfc *nfc, int column, int page)
{
        if (column != -1) {
                if (nfc->chip.options & NAND_BUSWIDTH_16)
                        column = column / 2;
                vf610_nfc_set_field(nfc, NFC_COL_ADDR, COL_ADDR_MASK,
                                    COL_ADDR_SHIFT, column);
        }
        if (page != -1)
                vf610_nfc_set_field(nfc, NFC_ROW_ADDR, ROW_ADDR_MASK,
                                    ROW_ADDR_SHIFT, page);
}

static inline void vf610_nfc_ecc_mode(struct vf610_nfc *nfc, int ecc_mode)
{
        vf610_nfc_set_field(nfc, NFC_FLASH_CONFIG,
                            CONFIG_ECC_MODE_MASK,
                            CONFIG_ECC_MODE_SHIFT, ecc_mode);
}

static inline void vf610_nfc_transfer_size(struct vf610_nfc *nfc, int size)
{
        vf610_nfc_write(nfc, NFC_SECTOR_SIZE, size);
}

static void vf610_nfc_command(struct mtd_info *mtd, unsigned command,
                              int column, int page)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        int trfr_sz = nfc->chip.options & NAND_BUSWIDTH_16 ? 1 : 0;

        nfc->buf_offset = max(column, 0);
        nfc->alt_buf = ALT_BUF_DATA;

        switch (command) {
        case NAND_CMD_SEQIN:
                /* Use valid column/page from preread... */
                vf610_nfc_addr_cycle(nfc, column, page);
                nfc->buf_offset = 0;

                /*
                 * SEQIN => data => PAGEPROG sequence is done by the controller
                 * hence we do not need to issue the command here...
                 */
                return;
        case NAND_CMD_PAGEPROG:
                trfr_sz += nfc->write_sz;
                vf610_nfc_transfer_size(nfc, trfr_sz);
                vf610_nfc_send_commands(nfc, NAND_CMD_SEQIN,
                                        command, PROGRAM_PAGE_CMD_CODE);
                if (nfc->use_hw_ecc)
                        vf610_nfc_ecc_mode(nfc, nfc->ecc_mode);
                else
                        vf610_nfc_ecc_mode(nfc, ECC_BYPASS);
                break;

        case NAND_CMD_RESET:
                vf610_nfc_transfer_size(nfc, 0);
                vf610_nfc_send_command(nfc, command, RESET_CMD_CODE);
                break;

        case NAND_CMD_READOOB:
                trfr_sz += mtd->oobsize;
                column = mtd->writesize;
                vf610_nfc_transfer_size(nfc, trfr_sz);
                vf610_nfc_send_commands(nfc, NAND_CMD_READ0,
                                        NAND_CMD_READSTART, READ_PAGE_CMD_CODE);
                vf610_nfc_addr_cycle(nfc, column, page);
                vf610_nfc_ecc_mode(nfc, ECC_BYPASS);
                break;

        case NAND_CMD_READ0:
                trfr_sz += mtd->writesize + mtd->oobsize;
                vf610_nfc_transfer_size(nfc, trfr_sz);
                vf610_nfc_send_commands(nfc, NAND_CMD_READ0,
                                        NAND_CMD_READSTART, READ_PAGE_CMD_CODE);
                vf610_nfc_addr_cycle(nfc, column, page);
                vf610_nfc_ecc_mode(nfc, nfc->ecc_mode);
                break;

        case NAND_CMD_PARAM:
                nfc->alt_buf = ALT_BUF_ONFI;
                trfr_sz = 3 * sizeof(struct nand_onfi_params);
                vf610_nfc_transfer_size(nfc, trfr_sz);
                vf610_nfc_send_command(nfc, command, READ_ONFI_PARAM_CMD_CODE);
                vf610_nfc_addr_cycle(nfc, -1, column);
                vf610_nfc_ecc_mode(nfc, ECC_BYPASS);
                break;

        case NAND_CMD_ERASE1:
                vf610_nfc_transfer_size(nfc, 0);
                vf610_nfc_send_commands(nfc, command,
                                        NAND_CMD_ERASE2, ERASE_CMD_CODE);
                vf610_nfc_addr_cycle(nfc, column, page);
                break;

        case NAND_CMD_READID:
                nfc->alt_buf = ALT_BUF_ID;
                nfc->buf_offset = 0;
                vf610_nfc_transfer_size(nfc, 0);
                vf610_nfc_send_command(nfc, command, READ_ID_CMD_CODE);
                vf610_nfc_addr_cycle(nfc, -1, column);
                break;

        case NAND_CMD_STATUS:
                nfc->alt_buf = ALT_BUF_STAT;
                vf610_nfc_transfer_size(nfc, 0);
                vf610_nfc_send_command(nfc, command, STATUS_READ_CMD_CODE);
                break;
        default:
                return;
        }

        vf610_nfc_done(nfc);

        nfc->use_hw_ecc = false;
        nfc->write_sz = 0;
}

static void vf610_nfc_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        uint c = nfc->buf_offset;

        /* Alternate buffers are only supported through read_byte */
        WARN_ON(nfc->alt_buf);

        vf610_nfc_memcpy(buf, nfc->regs + NFC_MAIN_AREA(0) + c, len);

        nfc->buf_offset += len;
}

static void vf610_nfc_write_buf(struct mtd_info *mtd, const uint8_t *buf,
                                int len)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        uint c = nfc->buf_offset;
        uint l;

        l = min_t(uint, len, mtd->writesize + mtd->oobsize - c);
        vf610_nfc_memcpy(nfc->regs + NFC_MAIN_AREA(0) + c, buf, l);

        nfc->write_sz += l;
        nfc->buf_offset += l;
}

static uint8_t vf610_nfc_read_byte(struct mtd_info *mtd)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        u8 tmp;
        uint c = nfc->buf_offset;

        switch (nfc->alt_buf) {
        case ALT_BUF_ID:
                tmp = vf610_nfc_get_id(nfc, c);
                break;
        case ALT_BUF_STAT:
                tmp = vf610_nfc_get_status(nfc);
                break;
#ifdef __LITTLE_ENDIAN
        case ALT_BUF_ONFI:
                /* Reverse byte since the controller uses big endianness */
                c = nfc->buf_offset ^ 0x3;
                /* fall-through */
#endif
        default:
                tmp = *((u8 *)(nfc->regs + NFC_MAIN_AREA(0) + c));
                break;
        }
        nfc->buf_offset++;
        return tmp;
}

static u16 vf610_nfc_read_word(struct mtd_info *mtd)
{
        u16 tmp;

        vf610_nfc_read_buf(mtd, (u_char *)&tmp, sizeof(tmp));
        return tmp;
}

/* If not provided, upper layers apply a fixed delay. */
static int vf610_nfc_dev_ready(struct mtd_info *mtd)
{
        /* NFC handles R/B internally; always ready.  */
        return 1;
}

/*
 * This function supports Vybrid only (MPC5125 would have full RB and four CS)
 */
static void vf610_nfc_select_chip(struct mtd_info *mtd, int chip)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        u32 tmp = vf610_nfc_read(nfc, NFC_ROW_ADDR);

        /* Vybrid only (MPC5125 would have full RB and four CS) */
        if (nfc->variant != NFC_VFC610)
                return;

        tmp &= ~(ROW_ADDR_CHIP_SEL_RB_MASK | ROW_ADDR_CHIP_SEL_MASK);

        if (chip >= 0) {
                tmp |= 1 << ROW_ADDR_CHIP_SEL_RB_SHIFT;
                tmp |= BIT(chip) << ROW_ADDR_CHIP_SEL_SHIFT;
        }

        vf610_nfc_write(nfc, NFC_ROW_ADDR, tmp);
}

/* Count the number of 0's in buff up to max_bits */
static inline int count_written_bits(uint8_t *buff, int size, int max_bits)
{
        uint32_t *buff32 = (uint32_t *)buff;
        int k, written_bits = 0;

        for (k = 0; k < (size / 4); k++) {
                written_bits += hweight32(~buff32[k]);
                if (unlikely(written_bits > max_bits))
                        break;
        }

        return written_bits;
}

static inline int vf610_nfc_correct_data(struct mtd_info *mtd, uint8_t *dat,
                                         uint8_t *oob, int page)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);
        u32 ecc_status_off = NFC_MAIN_AREA(0) + ECC_SRAM_ADDR + ECC_STATUS;
        u8 ecc_status;
        u8 ecc_count;
        int flips_threshold = nfc->chip.ecc.strength / 2;

        ecc_status = vf610_nfc_read(nfc, ecc_status_off) & 0xff;
        ecc_count = ecc_status & ECC_STATUS_ERR_COUNT;

        if (!(ecc_status & ECC_STATUS_MASK))
                return ecc_count;

        /* Read OOB without ECC unit enabled */
        vf610_nfc_command(mtd, NAND_CMD_READOOB, 0, page);
        vf610_nfc_read_buf(mtd, oob, mtd->oobsize);

        /*
         * On an erased page, bit count (including OOB) should be zero or
         * at least less then half of the ECC strength.
         */
        return nand_check_erased_ecc_chunk(dat, nfc->chip.ecc.size, oob,
                                           mtd->oobsize, NULL, 0,
                                           flips_threshold);
}

static int vf610_nfc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
                                uint8_t *buf, int oob_required, int page)
{
        int eccsize = chip->ecc.size;
        int stat;

        vf610_nfc_read_buf(mtd, buf, eccsize);
        if (oob_required)
                vf610_nfc_read_buf(mtd, chip->oob_poi, mtd->oobsize);

        stat = vf610_nfc_correct_data(mtd, buf, chip->oob_poi, page);

        if (stat < 0) {
                mtd->ecc_stats.failed++;
                return 0;
        } else {
                mtd->ecc_stats.corrected += stat;
                return stat;
        }
}

static int vf610_nfc_write_page(struct mtd_info *mtd, struct nand_chip *chip,
                                const uint8_t *buf, int oob_required, int page)
{
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);

        vf610_nfc_write_buf(mtd, buf, mtd->writesize);
        if (oob_required)
                vf610_nfc_write_buf(mtd, chip->oob_poi, mtd->oobsize);

        /* Always write whole page including OOB due to HW ECC */
        nfc->use_hw_ecc = true;
        nfc->write_sz = mtd->writesize + mtd->oobsize;

        return 0;
}

static const struct of_device_id vf610_nfc_dt_ids[] = {
        { .compatible = "fsl,vf610-nfc", .data = (void *)NFC_VFC610 },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, vf610_nfc_dt_ids);

static void vf610_nfc_preinit_controller(struct vf610_nfc *nfc)
{
        vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_16BIT);
        vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_ADDR_AUTO_INCR_BIT);
        vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_BUFNO_AUTO_INCR_BIT);
        vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_BOOT_MODE_BIT);
        vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_DMA_REQ_BIT);
        vf610_nfc_set(nfc, NFC_FLASH_CONFIG, CONFIG_FAST_FLASH_BIT);

        /* Disable virtual pages, only one elementary transfer unit */
        vf610_nfc_set_field(nfc, NFC_FLASH_CONFIG, CONFIG_PAGE_CNT_MASK,
                            CONFIG_PAGE_CNT_SHIFT, 1);
}

static void vf610_nfc_init_controller(struct vf610_nfc *nfc)
{
        if (nfc->chip.options & NAND_BUSWIDTH_16)
                vf610_nfc_set(nfc, NFC_FLASH_CONFIG, CONFIG_16BIT);
        else
                vf610_nfc_clear(nfc, NFC_FLASH_CONFIG, CONFIG_16BIT);

        if (nfc->chip.ecc.mode == NAND_ECC_HW) {
                /* Set ECC status offset in SRAM */
                vf610_nfc_set_field(nfc, NFC_FLASH_CONFIG,
                                    CONFIG_ECC_SRAM_ADDR_MASK,
                                    CONFIG_ECC_SRAM_ADDR_SHIFT,
                                    ECC_SRAM_ADDR >> 3);

                /* Enable ECC status in SRAM */
                vf610_nfc_set(nfc, NFC_FLASH_CONFIG, CONFIG_ECC_SRAM_REQ_BIT);
        }
}

static int vf610_nfc_probe(struct platform_device *pdev)
{
        struct vf610_nfc *nfc;
        struct resource *res;
        struct mtd_info *mtd;
        struct nand_chip *chip;
        struct device_node *child;
        const struct of_device_id *of_id;
        int err;
        int irq;

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

        nfc->dev = &pdev->dev;
        mtd = &nfc->mtd;
        chip = &nfc->chip;

        mtd->priv = chip;
        mtd->owner = THIS_MODULE;
        mtd->dev.parent = nfc->dev;
        mtd->name = DRV_NAME;

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

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        nfc->regs = devm_ioremap_resource(nfc->dev, res);
        if (IS_ERR(nfc->regs))
                return PTR_ERR(nfc->regs);

        nfc->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(nfc->clk))
                return PTR_ERR(nfc->clk);

        err = clk_prepare_enable(nfc->clk);
        if (err) {
                dev_err(nfc->dev, "Unable to enable clock!\n");
                return err;
        }

        of_id = of_match_device(vf610_nfc_dt_ids, &pdev->dev);
        nfc->variant = (enum vf610_nfc_variant)of_id->data;

        for_each_available_child_of_node(nfc->dev->of_node, child) {
                if (of_device_is_compatible(child, "fsl,vf610-nfc-nandcs")) {

                        if (chip->flash_node) {
                                dev_err(nfc->dev,
                                        "Only one NAND chip supported!\n");
                                err = -EINVAL;
                                goto error;
                        }

                        chip->flash_node = child;
                }
        }

        if (!chip->flash_node) {
                dev_err(nfc->dev, "NAND chip sub-node missing!\n");
                err = -ENODEV;
                goto err_clk;
        }

        chip->dev_ready = vf610_nfc_dev_ready;
        chip->cmdfunc = vf610_nfc_command;
        chip->read_byte = vf610_nfc_read_byte;
        chip->read_word = vf610_nfc_read_word;
        chip->read_buf = vf610_nfc_read_buf;
        chip->write_buf = vf610_nfc_write_buf;
        chip->select_chip = vf610_nfc_select_chip;

        chip->options |= NAND_NO_SUBPAGE_WRITE;

        init_completion(&nfc->cmd_done);

        err = devm_request_irq(nfc->dev, irq, vf610_nfc_irq, 0, DRV_NAME, mtd);
        if (err) {
                dev_err(nfc->dev, "Error requesting IRQ!\n");
                goto error;
        }

        vf610_nfc_preinit_controller(nfc);

        /* first scan to find the device and get the page size */
        if (nand_scan_ident(mtd, 1, NULL)) {
                err = -ENXIO;
                goto error;
        }

        vf610_nfc_init_controller(nfc);

        /* Bad block options. */
        if (chip->bbt_options & NAND_BBT_USE_FLASH)
                chip->bbt_options |= NAND_BBT_NO_OOB;

        /* Single buffer only, max 256 OOB minus ECC status */
        if (mtd->writesize + mtd->oobsize > PAGE_2K + OOB_MAX - 8) {
                dev_err(nfc->dev, "Unsupported flash page size\n");
                err = -ENXIO;
                goto error;
        }

        if (chip->ecc.mode == NAND_ECC_HW) {
                if (mtd->writesize != PAGE_2K && mtd->oobsize < 64) {
                        dev_err(nfc->dev, "Unsupported flash with hwecc\n");
                        err = -ENXIO;
                        goto error;
                }

                if (chip->ecc.size != mtd->writesize) {
                        dev_err(nfc->dev, "Step size needs to be page size\n");
                        err = -ENXIO;
                        goto error;
                }

                /* Only 64 byte ECC layouts known */
                if (mtd->oobsize > 64)
                        mtd->oobsize = 64;

                if (chip->ecc.strength == 32) {
                        nfc->ecc_mode = ECC_60_BYTE;
                        chip->ecc.bytes = 60;
                        chip->ecc.layout = &vf610_nfc_ecc60;
                } else if (chip->ecc.strength == 24) {
                        nfc->ecc_mode = ECC_45_BYTE;
                        chip->ecc.bytes = 45;
                        chip->ecc.layout = &vf610_nfc_ecc45;
                } else {
                        dev_err(nfc->dev, "Unsupported ECC strength\n");
                        err = -ENXIO;
                        goto error;
                }

                /* propagate ecc.layout to mtd_info */
                mtd->ecclayout = chip->ecc.layout;
                chip->ecc.read_page = vf610_nfc_read_page;
                chip->ecc.write_page = vf610_nfc_write_page;

                chip->ecc.size = PAGE_2K;
        }

        /* second phase scan */
        if (nand_scan_tail(mtd)) {
                err = -ENXIO;
                goto error;
        }

        platform_set_drvdata(pdev, mtd);

        /* Register device in MTD */
        return mtd_device_parse_register(mtd, NULL,
                &(struct mtd_part_parser_data){
                        .of_node = chip->flash_node,
                },
                NULL, 0);

error:
        of_node_put(chip->flash_node);
err_clk:
        clk_disable_unprepare(nfc->clk);
        return err;
}

static int vf610_nfc_remove(struct platform_device *pdev)
{
        struct mtd_info *mtd = platform_get_drvdata(pdev);
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);

        nand_release(mtd);
        clk_disable_unprepare(nfc->clk);
        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int vf610_nfc_suspend(struct device *dev)
{
        struct mtd_info *mtd = dev_get_drvdata(dev);
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);

        clk_disable_unprepare(nfc->clk);
        return 0;
}

static int vf610_nfc_resume(struct device *dev)
{
        struct mtd_info *mtd = dev_get_drvdata(dev);
        struct vf610_nfc *nfc = mtd_to_nfc(mtd);

        pinctrl_pm_select_default_state(dev);

        clk_prepare_enable(nfc->clk);

        vf610_nfc_preinit_controller(nfc);
        vf610_nfc_init_controller(nfc);
        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(vf610_nfc_pm_ops, vf610_nfc_suspend, vf610_nfc_resume);

static struct platform_driver vf610_nfc_driver = {
        .driver         = {
                .name   = DRV_NAME,
                .of_match_table = vf610_nfc_dt_ids,
                .pm     = &vf610_nfc_pm_ops,
        },
        .probe          = vf610_nfc_probe,
        .remove         = vf610_nfc_remove,
};

module_platform_driver(vf610_nfc_driver);

MODULE_AUTHOR("Stefan Agner <stefan.agner@toradex.com>");
MODULE_DESCRIPTION("Freescale VF610/MPC5125 NFC MTD NAND driver");
MODULE_LICENSE("GPL");