// SPDX-License-Identifier: GPL-2.0+
/*
 * (C) Copyright 2016 Xilinx, Inc.
 *
 * Xilinx Zynq NAND Flash Controller Driver
 * This driver is based on plat_nand.c and mxc_nand.c drivers
 */

#include <common.h>
#include <malloc.h>
#include <asm/io.h>
#include <linux/errno.h>
#include <nand.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/nand_ecc.h>
#include <asm/arch/hardware.h>
#include <asm/arch/sys_proto.h>

/* The NAND flash driver defines */
#define ZYNQ_NAND_CMD_PHASE             1
#define ZYNQ_NAND_DATA_PHASE            2
#define ZYNQ_NAND_ECC_SIZE              512
#define ZYNQ_NAND_SET_OPMODE_8BIT       (0 << 0)
#define ZYNQ_NAND_SET_OPMODE_16BIT      (1 << 0)
#define ZYNQ_NAND_ECC_STATUS            (1 << 6)
#define ZYNQ_MEMC_CLRCR_INT_CLR1        (1 << 4)
#define ZYNQ_MEMC_SR_RAW_INT_ST1        (1 << 6)
#define ZYNQ_MEMC_SR_INT_ST1            (1 << 4)
#define ZYNQ_MEMC_NAND_ECC_MODE_MASK    0xC

/* Flash memory controller operating parameters */
#define ZYNQ_NAND_CLR_CONFIG    ((0x1 << 1)  |  /* Disable interrupt */ \
                                (0x1 << 4)   |  /* Clear interrupt */ \
                                (0x1 << 6))     /* Disable ECC interrupt */

#ifndef CONFIG_NAND_ZYNQ_USE_BOOTLOADER1_TIMINGS

/* Assuming 50MHz clock (20ns cycle time) and 3V operation */
#define ZYNQ_NAND_SET_CYCLES    ((0x2 << 20) |  /* t_rr from nand_cycles */ \
                                (0x2 << 17)  |  /* t_ar from nand_cycles */ \
                                (0x1 << 14)  |  /* t_clr from nand_cycles */ \
                                (0x3 << 11)  |  /* t_wp from nand_cycles */ \
                                (0x2 << 8)   |  /* t_rea from nand_cycles */ \
                                (0x5 << 4)   |  /* t_wc from nand_cycles */ \
                                (0x5 << 0))     /* t_rc from nand_cycles */
#endif


#define ZYNQ_NAND_DIRECT_CMD    ((0x4 << 23) |  /* Chip 0 from interface 1 */ \
                                (0x2 << 21))    /* UpdateRegs operation */

#define ZYNQ_NAND_ECC_CONFIG    ((0x1 << 2)  |  /* ECC available on APB */ \
                                (0x1 << 4)   |  /* ECC read at end of page */ \
                                (0x0 << 5))     /* No Jumping */

#define ZYNQ_NAND_ECC_CMD1      ((0x80)      |  /* Write command */ \
                                (0x00 << 8)  |  /* Read command */ \
                                (0x30 << 16) |  /* Read End command */ \
                                (0x1 << 24))    /* Read End command calid */

#define ZYNQ_NAND_ECC_CMD2      ((0x85)      |  /* Write col change cmd */ \
                                (0x05 << 8)  |  /* Read col change cmd */ \
                                (0xE0 << 16) |  /* Read col change end cmd */ \
                                (0x1 << 24))    /* Read col change
                                                        end cmd valid */
/* AXI Address definitions */
#define START_CMD_SHIFT                 3
#define END_CMD_SHIFT                   11
#define END_CMD_VALID_SHIFT             20
#define ADDR_CYCLES_SHIFT               21
#define CLEAR_CS_SHIFT                  21
#define ECC_LAST_SHIFT                  10
#define COMMAND_PHASE                   (0 << 19)
#define DATA_PHASE                      (1 << 19)
#define ONDIE_ECC_FEATURE_ADDR          0x90
#define ONDIE_ECC_FEATURE_ENABLE        0x08

#define ZYNQ_NAND_ECC_LAST      (1 << ECC_LAST_SHIFT)   /* Set ECC_Last */
#define ZYNQ_NAND_CLEAR_CS      (1 << CLEAR_CS_SHIFT)   /* Clear chip select */

/* ECC block registers bit position and bit mask */
#define ZYNQ_NAND_ECC_BUSY      (1 << 6)        /* ECC block is busy */
#define ZYNQ_NAND_ECC_MASK      0x00FFFFFF      /* ECC value mask */

#define ZYNQ_NAND_ROW_ADDR_CYCL_MASK    0x0F
#define ZYNQ_NAND_COL_ADDR_CYCL_MASK    0xF0

#define ZYNQ_NAND_MIO_NUM_NAND_8BIT     13
#define ZYNQ_NAND_MIO_NUM_NAND_16BIT    8

enum zynq_nand_bus_width {
        NAND_BW_UNKNOWN = -1,
        NAND_BW_8BIT,
        NAND_BW_16BIT,
};

#ifndef NAND_CMD_LOCK_TIGHT
#define NAND_CMD_LOCK_TIGHT 0x2c
#endif

#ifndef NAND_CMD_LOCK_STATUS
#define NAND_CMD_LOCK_STATUS 0x7a
#endif

/* SMC register set */
struct zynq_nand_smc_regs {
        u32 csr;                /* 0x00 */
        u32 reserved0[2];
        u32 cfr;                /* 0x0C */
        u32 dcr;                /* 0x10 */
        u32 scr;                /* 0x14 */
        u32 sor;                /* 0x18 */
        u32 reserved1[249];
        u32 esr;                /* 0x400 */
        u32 emcr;               /* 0x404 */
        u32 emcmd1r;            /* 0x408 */
        u32 emcmd2r;            /* 0x40C */
        u32 reserved2[2];
        u32 eval0r;             /* 0x418 */
};
#define zynq_nand_smc_base      ((struct zynq_nand_smc_regs __iomem *)\
                                ZYNQ_SMC_BASEADDR)

/*
 * struct zynq_nand_info - Defines the NAND flash driver instance
 * @parts:              Pointer to the mtd_partition structure
 * @nand_base:          Virtual address of the NAND flash device
 * @end_cmd_pending:    End command is pending
 * @end_cmd:            End command
 */
struct zynq_nand_info {
        void __iomem    *nand_base;
        u8              end_cmd_pending;
        u8              end_cmd;
};

/*
 * struct zynq_nand_command_format - Defines NAND flash command format
 * @start_cmd:          First cycle command (Start command)
 * @end_cmd:            Second cycle command (Last command)
 * @addr_cycles:        Number of address cycles required to send the address
 * @end_cmd_valid:      The second cycle command is valid for cmd or data phase
 */
struct zynq_nand_command_format {
        u8 start_cmd;
        u8 end_cmd;
        u8 addr_cycles;
        u8 end_cmd_valid;
};

/*  The NAND flash operations command format */
static const struct zynq_nand_command_format zynq_nand_commands[] = {
        {NAND_CMD_READ0, NAND_CMD_READSTART, 5, ZYNQ_NAND_CMD_PHASE},
        {NAND_CMD_RNDOUT, NAND_CMD_RNDOUTSTART, 2, ZYNQ_NAND_CMD_PHASE},
        {NAND_CMD_READID, NAND_CMD_NONE, 1, 0},
        {NAND_CMD_STATUS, NAND_CMD_NONE, 0, 0},
        {NAND_CMD_SEQIN, NAND_CMD_PAGEPROG, 5, ZYNQ_NAND_DATA_PHASE},
        {NAND_CMD_RNDIN, NAND_CMD_NONE, 2, 0},
        {NAND_CMD_ERASE1, NAND_CMD_ERASE2, 3, ZYNQ_NAND_CMD_PHASE},
        {NAND_CMD_RESET, NAND_CMD_NONE, 0, 0},
        {NAND_CMD_PARAM, NAND_CMD_NONE, 1, 0},
        {NAND_CMD_GET_FEATURES, NAND_CMD_NONE, 1, 0},
        {NAND_CMD_SET_FEATURES, NAND_CMD_NONE, 1, 0},
        {NAND_CMD_LOCK, NAND_CMD_NONE, 0, 0},
        {NAND_CMD_LOCK_TIGHT, NAND_CMD_NONE, 0, 0},
        {NAND_CMD_UNLOCK1, NAND_CMD_NONE, 3, 0},
        {NAND_CMD_UNLOCK2, NAND_CMD_NONE, 3, 0},
        {NAND_CMD_LOCK_STATUS, NAND_CMD_NONE, 3, 0},
        {NAND_CMD_NONE, NAND_CMD_NONE, 0, 0},
        /* Add all the flash commands supported by the flash device */
};

/* Define default oob placement schemes for large and small page devices */
static struct nand_ecclayout nand_oob_16 = {
        .eccbytes = 3,
        .eccpos = {0, 1, 2},
        .oobfree = {
                { .offset = 8, .length = 8 }
        }
};

static struct nand_ecclayout nand_oob_64 = {
        .eccbytes = 12,
        .eccpos = {
                   52, 53, 54, 55, 56, 57,
                   58, 59, 60, 61, 62, 63},
        .oobfree = {
                { .offset = 2, .length = 50 }
        }
};

static struct nand_ecclayout ondie_nand_oob_64 = {
        .eccbytes = 32,

        .eccpos = {
                8, 9, 10, 11, 12, 13, 14, 15,
                24, 25, 26, 27, 28, 29, 30, 31,
                40, 41, 42, 43, 44, 45, 46, 47,
                56, 57, 58, 59, 60, 61, 62, 63
        },

        .oobfree = {
                { .offset = 4, .length = 4 },
                { .offset = 20, .length = 4 },
                { .offset = 36, .length = 4 },
                { .offset = 52, .length = 4 }
        }
};

/* bbt decriptors for chips with on-die ECC and
   chips with 64-byte OOB */
static u8 bbt_pattern[] = {'B', 'b', 't', '0' };
static u8 mirror_pattern[] = {'1', 't', 'b', 'B' };

static struct nand_bbt_descr bbt_main_descr = {
        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE |
                NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
        .offs = 4,
        .len = 4,
        .veroffs = 20,
        .maxblocks = 4,
        .pattern = bbt_pattern
};

static struct nand_bbt_descr bbt_mirror_descr = {
        .options = NAND_BBT_LASTBLOCK | NAND_BBT_CREATE | NAND_BBT_WRITE |
                NAND_BBT_2BIT | NAND_BBT_VERSION | NAND_BBT_PERCHIP,
        .offs = 4,
        .len = 4,
        .veroffs = 20,
        .maxblocks = 4,
        .pattern = mirror_pattern
};

/*
 * zynq_nand_waitfor_ecc_completion - Wait for ECC completion
 *
 * returns: status for command completion, -1 for Timeout
 */
static int zynq_nand_waitfor_ecc_completion(void)
{
        unsigned long timeout;
        u32 status;

        /* Wait max 10us */
        timeout = 10;
        status = readl(&zynq_nand_smc_base->esr);
        while (status & ZYNQ_NAND_ECC_BUSY) {
                status = readl(&zynq_nand_smc_base->esr);
                if (timeout == 0)
                        return -1;
                timeout--;
                udelay(1);
        }

        return status;
}

/*
 * zynq_nand_init_nand_flash - Initialize NAND controller
 * @option:     Device property flags
 *
 * This function initializes the NAND flash interface on the NAND controller.
 *
 * returns:     0 on success or error value on failure
 */
static int zynq_nand_init_nand_flash(int option)
{
        u32 status;

        /* disable interrupts */
        writel(ZYNQ_NAND_CLR_CONFIG, &zynq_nand_smc_base->cfr);
#ifndef CONFIG_NAND_ZYNQ_USE_BOOTLOADER1_TIMINGS
        /* Initialize the NAND interface by setting cycles and operation mode */
        writel(ZYNQ_NAND_SET_CYCLES, &zynq_nand_smc_base->scr);
#endif
        if (option & NAND_BUSWIDTH_16)
                writel(ZYNQ_NAND_SET_OPMODE_16BIT, &zynq_nand_smc_base->sor);
        else
                writel(ZYNQ_NAND_SET_OPMODE_8BIT, &zynq_nand_smc_base->sor);

        writel(ZYNQ_NAND_DIRECT_CMD, &zynq_nand_smc_base->dcr);

        /* Wait till the ECC operation is complete */
        status = zynq_nand_waitfor_ecc_completion();
        if (status < 0) {
                printf("%s: Timeout\n", __func__);
                return status;
        }

        /* Set the command1 and command2 register */
        writel(ZYNQ_NAND_ECC_CMD1, &zynq_nand_smc_base->emcmd1r);
        writel(ZYNQ_NAND_ECC_CMD2, &zynq_nand_smc_base->emcmd2r);

        return 0;
}

/*
 * zynq_nand_calculate_hwecc - Calculate Hardware ECC
 * @mtd:        Pointer to the mtd_info structure
 * @data:       Pointer to the page data
 * @ecc_code:   Pointer to the ECC buffer where ECC data needs to be stored
 *
 * This function retrieves the Hardware ECC data from the controller and returns
 * ECC data back to the MTD subsystem.
 *
 * returns:     0 on success or error value on failure
 */
static int zynq_nand_calculate_hwecc(struct mtd_info *mtd, const u8 *data,
                u8 *ecc_code)
{
        u32 ecc_value = 0;
        u8 ecc_reg, ecc_byte;
        u32 ecc_status;

        /* Wait till the ECC operation is complete */
        ecc_status = zynq_nand_waitfor_ecc_completion();
        if (ecc_status < 0) {
                printf("%s: Timeout\n", __func__);
                return ecc_status;
        }

        for (ecc_reg = 0; ecc_reg < 4; ecc_reg++) {
                /* Read ECC value for each block */
                ecc_value = readl(&zynq_nand_smc_base->eval0r + ecc_reg);

                /* Get the ecc status from ecc read value */
                ecc_status = (ecc_value >> 24) & 0xFF;

                /* ECC value valid */
                if (ecc_status & ZYNQ_NAND_ECC_STATUS) {
                        for (ecc_byte = 0; ecc_byte < 3; ecc_byte++) {
                                /* Copy ECC bytes to MTD buffer */
                                *ecc_code = ecc_value & 0xFF;
                                ecc_value = ecc_value >> 8;
                                ecc_code++;
                        }
                } else {
                        debug("%s: ecc status failed\n", __func__);
                }
        }

        return 0;
}

/*
 * onehot - onehot function
 * @value:      value to check for onehot
 *
 * This function checks whether a value is onehot or not.
 * onehot is if and only if one bit is set.
 *
 * FIXME: Try to move this in common.h
 */
static bool onehot(unsigned short value)
{
        bool onehot;

        onehot = value && !(value & (value - 1));
        return onehot;
}

/*
 * zynq_nand_correct_data - ECC correction function
 * @mtd:        Pointer to the mtd_info structure
 * @buf:        Pointer to the page data
 * @read_ecc:   Pointer to the ECC value read from spare data area
 * @calc_ecc:   Pointer to the calculated ECC value
 *
 * This function corrects the ECC single bit errors & detects 2-bit errors.
 *
 * returns:     0 if no ECC errors found
 *              1 if single bit error found and corrected.
 *              -1 if multiple ECC errors found.
 */
static int zynq_nand_correct_data(struct mtd_info *mtd, unsigned char *buf,
                        unsigned char *read_ecc, unsigned char *calc_ecc)
{
        unsigned char bit_addr;
        unsigned int byte_addr;
        unsigned short ecc_odd, ecc_even;
        unsigned short read_ecc_lower, read_ecc_upper;
        unsigned short calc_ecc_lower, calc_ecc_upper;

        read_ecc_lower = (read_ecc[0] | (read_ecc[1] << 8)) & 0xfff;
        read_ecc_upper = ((read_ecc[1] >> 4) | (read_ecc[2] << 4)) & 0xfff;

        calc_ecc_lower = (calc_ecc[0] | (calc_ecc[1] << 8)) & 0xfff;
        calc_ecc_upper = ((calc_ecc[1] >> 4) | (calc_ecc[2] << 4)) & 0xfff;

        ecc_odd = read_ecc_lower ^ calc_ecc_lower;
        ecc_even = read_ecc_upper ^ calc_ecc_upper;

        if ((ecc_odd == 0) && (ecc_even == 0))
                return 0;       /* no error */

        if (ecc_odd == (~ecc_even & 0xfff)) {
                /* bits [11:3] of error code is byte offset */
                byte_addr = (ecc_odd >> 3) & 0x1ff;
                /* bits [2:0] of error code is bit offset */
                bit_addr = ecc_odd & 0x7;
                /* Toggling error bit */
                buf[byte_addr] ^= (1 << bit_addr);
                return 1;
        }

        if (onehot(ecc_odd | ecc_even))
                return 1; /* one error in parity */

        return -1; /* Uncorrectable error */
}

/*
 * zynq_nand_read_oob - [REPLACABLE] the most common OOB data read function
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @page:       page number to read
 * @sndcmd:     flag whether to issue read command or not
 */
static int zynq_nand_read_oob(struct mtd_info *mtd, struct nand_chip *chip,
                        int page)
{
        unsigned long data_phase_addr = 0;
        int data_width = 4;
        u8 *p;

        chip->cmdfunc(mtd, NAND_CMD_READOOB, 0, page);

        p = chip->oob_poi;
        chip->read_buf(mtd, p, (mtd->oobsize - data_width));
        p += mtd->oobsize - data_width;

        data_phase_addr = (unsigned long)chip->IO_ADDR_R;
        data_phase_addr |= ZYNQ_NAND_CLEAR_CS;
        chip->IO_ADDR_R = (void __iomem *)data_phase_addr;
        chip->read_buf(mtd, p, data_width);

        return 0;
}

/*
 * zynq_nand_write_oob - [REPLACABLE] the most common OOB data write function
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @page:       page number to write
 */
static int zynq_nand_write_oob(struct mtd_info *mtd, struct nand_chip *chip,
                             int page)
{
        int status = 0, data_width = 4;
        const u8 *buf = chip->oob_poi;
        unsigned long data_phase_addr = 0;

        chip->cmdfunc(mtd, NAND_CMD_SEQIN, mtd->writesize, page);

        chip->write_buf(mtd, buf, (mtd->oobsize - data_width));
        buf += mtd->oobsize - data_width;

        data_phase_addr = (unsigned long)chip->IO_ADDR_W;
        data_phase_addr |= ZYNQ_NAND_CLEAR_CS;
        data_phase_addr |= (1 << END_CMD_VALID_SHIFT);
        chip->IO_ADDR_W = (void __iomem *)data_phase_addr;
        chip->write_buf(mtd, buf, data_width);

        /* Send command to program the OOB data */
        chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1);
        status = chip->waitfunc(mtd, chip);

        return status & NAND_STATUS_FAIL ? -EIO : 0;
}

/*
 * zynq_nand_read_page_raw - [Intern] read raw page data without ecc
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @buf:        buffer to store read data
 * @oob_required: must write chip->oob_poi to OOB
 * @page:       page number to read
 */
static int zynq_nand_read_page_raw(struct mtd_info *mtd, struct nand_chip *chip,
                                   u8 *buf,  int oob_required, int page)
{
        unsigned long data_width = 4;
        unsigned long data_phase_addr = 0;
        u8 *p;

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

        p = chip->oob_poi;
        chip->read_buf(mtd, p, (mtd->oobsize - data_width));
        p += (mtd->oobsize - data_width);

        data_phase_addr = (unsigned long)chip->IO_ADDR_R;
        data_phase_addr |= ZYNQ_NAND_CLEAR_CS;
        chip->IO_ADDR_R = (void __iomem *)data_phase_addr;

        chip->read_buf(mtd, p, data_width);
        return 0;
}

static int zynq_nand_read_page_raw_nooob(struct mtd_info *mtd,
                struct nand_chip *chip, u8 *buf, int oob_required, int page)
{
        chip->read_buf(mtd, buf, mtd->writesize);
        return 0;
}

static int zynq_nand_read_subpage_raw(struct mtd_info *mtd,
                                    struct nand_chip *chip, u32 data_offs,
                                    u32 readlen, u8 *buf, int page)
{
        if (data_offs != 0) {
                chip->cmdfunc(mtd, NAND_CMD_RNDOUT, data_offs, -1);
                buf += data_offs;
        }
        chip->read_buf(mtd, buf, readlen);

        return 0;
}

/*
 * zynq_nand_write_page_raw - [Intern] raw page write function
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @buf:        data buffer
 * @oob_required: must write chip->oob_poi to OOB
 */
static int zynq_nand_write_page_raw(struct mtd_info *mtd,
        struct nand_chip *chip, const u8 *buf, int oob_required, int page)
{
        unsigned long data_width = 4;
        unsigned long data_phase_addr = 0;
        u8 *p;

        chip->write_buf(mtd, buf, mtd->writesize);

        p = chip->oob_poi;
        chip->write_buf(mtd, p, (mtd->oobsize - data_width));
        p += (mtd->oobsize - data_width);

        data_phase_addr = (unsigned long)chip->IO_ADDR_W;
        data_phase_addr |= ZYNQ_NAND_CLEAR_CS;
        data_phase_addr |= (1 << END_CMD_VALID_SHIFT);
        chip->IO_ADDR_W = (void __iomem *)data_phase_addr;

        chip->write_buf(mtd, p, data_width);

        return 0;
}

/*
 * nand_write_page_hwecc - Hardware ECC based page write function
 * @mtd:        Pointer to the mtd info structure
 * @chip:       Pointer to the NAND chip info structure
 * @buf:        Pointer to the data buffer
 * @oob_required: must write chip->oob_poi to OOB
 *
 * This functions writes data and hardware generated ECC values in to the page.
 */
static int zynq_nand_write_page_hwecc(struct mtd_info *mtd,
        struct nand_chip *chip, const u8 *buf, int oob_required, int page)
{
        int i, eccsteps, eccsize = chip->ecc.size;
        u8 *ecc_calc = chip->buffers->ecccalc;
        const u8 *p = buf;
        u32 *eccpos = chip->ecc.layout->eccpos;
        unsigned long data_phase_addr = 0;
        unsigned long data_width = 4;
        u8 *oob_ptr;

        for (eccsteps = chip->ecc.steps; (eccsteps - 1); eccsteps--) {
                chip->write_buf(mtd, p, eccsize);
                p += eccsize;
        }
        chip->write_buf(mtd, p, (eccsize - data_width));
        p += eccsize - data_width;

        /* Set ECC Last bit to 1 */
        data_phase_addr = (unsigned long) chip->IO_ADDR_W;
        data_phase_addr |= ZYNQ_NAND_ECC_LAST;
        chip->IO_ADDR_W = (void __iomem *)data_phase_addr;
        chip->write_buf(mtd, p, data_width);

        /* Wait for ECC to be calculated and read the error values */
        p = buf;
        chip->ecc.calculate(mtd, p, &ecc_calc[0]);

        for (i = 0; i < chip->ecc.total; i++)
                chip->oob_poi[eccpos[i]] = ~(ecc_calc[i]);

        /* Clear ECC last bit */
        data_phase_addr = (unsigned long)chip->IO_ADDR_W;
        data_phase_addr &= ~ZYNQ_NAND_ECC_LAST;
        chip->IO_ADDR_W = (void __iomem *)data_phase_addr;

        /* Write the spare area with ECC bytes */
        oob_ptr = chip->oob_poi;
        chip->write_buf(mtd, oob_ptr, (mtd->oobsize - data_width));

        data_phase_addr = (unsigned long)chip->IO_ADDR_W;
        data_phase_addr |= ZYNQ_NAND_CLEAR_CS;
        data_phase_addr |= (1 << END_CMD_VALID_SHIFT);
        chip->IO_ADDR_W = (void __iomem *)data_phase_addr;
        oob_ptr += (mtd->oobsize - data_width);
        chip->write_buf(mtd, oob_ptr, data_width);

        return 0;
}

/*
 * zynq_nand_write_page_swecc - [REPLACABLE] software ecc based page
 * write function
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @buf:        data buffer
 * @oob_required: must write chip->oob_poi to OOB
 */
static int zynq_nand_write_page_swecc(struct mtd_info *mtd,
        struct nand_chip *chip, const u8 *buf, int oob_required, int page)
{
        int i, eccsize = chip->ecc.size;
        int eccbytes = chip->ecc.bytes;
        int eccsteps = chip->ecc.steps;
        u8 *ecc_calc = chip->buffers->ecccalc;
        const u8 *p = buf;
        u32 *eccpos = chip->ecc.layout->eccpos;

        /* Software ecc calculation */
        for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize)
                chip->ecc.calculate(mtd, p, &ecc_calc[i]);

        for (i = 0; i < chip->ecc.total; i++)
                chip->oob_poi[eccpos[i]] = ecc_calc[i];

        return chip->ecc.write_page_raw(mtd, chip, buf, 1, page);
}

/*
 * nand_read_page_hwecc - Hardware ECC based page read function
 * @mtd:        Pointer to the mtd info structure
 * @chip:       Pointer to the NAND chip info structure
 * @buf:        Pointer to the buffer to store read data
 * @oob_required: must write chip->oob_poi to OOB
 * @page:       page number to read
 *
 * This functions reads data and checks the data integrity by comparing hardware
 * generated ECC values and read ECC values from spare area.
 *
 * returns:     0 always and updates ECC operation status in to MTD structure
 */
static int zynq_nand_read_page_hwecc(struct mtd_info *mtd,
        struct nand_chip *chip, u8 *buf, int oob_required, int page)
{
        int i, stat, eccsteps, eccsize = chip->ecc.size;
        int eccbytes = chip->ecc.bytes;
        u8 *p = buf;
        u8 *ecc_calc = chip->buffers->ecccalc;
        u8 *ecc_code = chip->buffers->ecccode;
        u32 *eccpos = chip->ecc.layout->eccpos;
        unsigned long data_phase_addr = 0;
        unsigned long data_width = 4;
        u8 *oob_ptr;

        for (eccsteps = chip->ecc.steps; (eccsteps - 1); eccsteps--) {
                chip->read_buf(mtd, p, eccsize);
                p += eccsize;
        }
        chip->read_buf(mtd, p, (eccsize - data_width));
        p += eccsize - data_width;

        /* Set ECC Last bit to 1 */
        data_phase_addr = (unsigned long)chip->IO_ADDR_R;
        data_phase_addr |= ZYNQ_NAND_ECC_LAST;
        chip->IO_ADDR_R = (void __iomem *)data_phase_addr;
        chip->read_buf(mtd, p, data_width);

        /* Read the calculated ECC value */
        p = buf;
        chip->ecc.calculate(mtd, p, &ecc_calc[0]);

        /* Clear ECC last bit */
        data_phase_addr = (unsigned long)chip->IO_ADDR_R;
        data_phase_addr &= ~ZYNQ_NAND_ECC_LAST;
        chip->IO_ADDR_R = (void __iomem *)data_phase_addr;

        /* Read the stored ECC value */
        oob_ptr = chip->oob_poi;
        chip->read_buf(mtd, oob_ptr, (mtd->oobsize - data_width));

        /* de-assert chip select */
        data_phase_addr = (unsigned long)chip->IO_ADDR_R;
        data_phase_addr |= ZYNQ_NAND_CLEAR_CS;
        chip->IO_ADDR_R = (void __iomem *)data_phase_addr;

        oob_ptr += (mtd->oobsize - data_width);
        chip->read_buf(mtd, oob_ptr, data_width);

        for (i = 0; i < chip->ecc.total; i++)
                ecc_code[i] = ~(chip->oob_poi[eccpos[i]]);

        eccsteps = chip->ecc.steps;
        p = buf;

        /* Check ECC error for all blocks and correct if it is correctable */
        for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
                stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
                if (stat < 0)
                        mtd->ecc_stats.failed++;
                else
                        mtd->ecc_stats.corrected += stat;
        }
        return 0;
}

/*
 * zynq_nand_read_page_swecc - [REPLACABLE] software ecc based page
 * read function
 * @mtd:        mtd info structure
 * @chip:       nand chip info structure
 * @buf:        buffer to store read data
 * @page:       page number to read
 */
static int zynq_nand_read_page_swecc(struct mtd_info *mtd,
        struct nand_chip *chip, u8 *buf, int oob_required,  int page)
{
        int i, eccsize = chip->ecc.size;
        int eccbytes = chip->ecc.bytes;
        int eccsteps = chip->ecc.steps;
        u8 *p = buf;
        u8 *ecc_calc = chip->buffers->ecccalc;
        u8 *ecc_code = chip->buffers->ecccode;
        u32 *eccpos = chip->ecc.layout->eccpos;

        chip->ecc.read_page_raw(mtd, chip, buf, 1, page);

        for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize)
                chip->ecc.calculate(mtd, p, &ecc_calc[i]);

        for (i = 0; i < chip->ecc.total; i++)
                ecc_code[i] = chip->oob_poi[eccpos[i]];

        eccsteps = chip->ecc.steps;
        p = buf;

        for (i = 0; eccsteps; eccsteps--, i += eccbytes, p += eccsize) {
                int stat;

                stat = chip->ecc.correct(mtd, p, &ecc_code[i], &ecc_calc[i]);
                if (stat < 0)
                        mtd->ecc_stats.failed++;
                else
                        mtd->ecc_stats.corrected += stat;
        }
        return 0;
}

/*
 * zynq_nand_select_chip - Select the flash device
 * @mtd:        Pointer to the mtd_info structure
 * @chip:       Chip number to be selected
 *
 * This function is empty as the NAND controller handles chip select line
 * internally based on the chip address passed in command and data phase.
 */
static void zynq_nand_select_chip(struct mtd_info *mtd, int chip)
{
        /* Not support multiple chips yet */
}

/*
 * zynq_nand_cmd_function - Send command to NAND device
 * @mtd:        Pointer to the mtd_info structure
 * @command:    The command to be sent to the flash device
 * @column:     The column address for this command, -1 if none
 * @page_addr:  The page address for this command, -1 if none
 */
static void zynq_nand_cmd_function(struct mtd_info *mtd, unsigned int command,
                                 int column, int page_addr)
{
        struct nand_chip *chip = mtd->priv;
        const struct zynq_nand_command_format *curr_cmd = NULL;
        u8 addr_cycles = 0;
        struct zynq_nand_info *xnand = (struct zynq_nand_info *)chip->priv;
        void *cmd_addr;
        unsigned long cmd_data = 0;
        unsigned long cmd_phase_addr = 0;
        unsigned long data_phase_addr = 0;
        u8 end_cmd = 0;
        u8 end_cmd_valid = 0;
        u32 index;

        if (xnand->end_cmd_pending) {
                /* Check for end command if this command request is same as the
                 * pending command then return
                 */
                if (xnand->end_cmd == command) {
                        xnand->end_cmd = 0;
                        xnand->end_cmd_pending = 0;
                        return;
                }
        }

        /* Emulate NAND_CMD_READOOB for large page device */
        if ((mtd->writesize > ZYNQ_NAND_ECC_SIZE) &&
            (command == NAND_CMD_READOOB)) {
                column += mtd->writesize;
                command = NAND_CMD_READ0;
        }

        /* Get the command format */
        for (index = 0; index < ARRAY_SIZE(zynq_nand_commands); index++)
                if (command == zynq_nand_commands[index].start_cmd)
                        break;

        if (index == ARRAY_SIZE(zynq_nand_commands)) {
                printf("%s: Unsupported start cmd %02x\n", __func__, command);
                return;
        }
        curr_cmd = &zynq_nand_commands[index];

        /* Clear interrupt */
        writel(ZYNQ_MEMC_CLRCR_INT_CLR1, &zynq_nand_smc_base->cfr);

        /* Get the command phase address */
        if (curr_cmd->end_cmd_valid == ZYNQ_NAND_CMD_PHASE)
                end_cmd_valid = 1;

        if (curr_cmd->end_cmd == NAND_CMD_NONE)
                end_cmd = 0x0;
        else
                end_cmd = curr_cmd->end_cmd;

        if (command == NAND_CMD_READ0 ||
            command == NAND_CMD_SEQIN) {
                addr_cycles = chip->onfi_params.addr_cycles &
                                ZYNQ_NAND_ROW_ADDR_CYCL_MASK;
                addr_cycles += ((chip->onfi_params.addr_cycles &
                                ZYNQ_NAND_COL_ADDR_CYCL_MASK) >> 4);
        } else {
                addr_cycles = curr_cmd->addr_cycles;
        }

        cmd_phase_addr = (unsigned long)xnand->nand_base        |
                        (addr_cycles << ADDR_CYCLES_SHIFT)      |
                        (end_cmd_valid << END_CMD_VALID_SHIFT)          |
                        (COMMAND_PHASE)                                 |
                        (end_cmd << END_CMD_SHIFT)                      |
                        (curr_cmd->start_cmd << START_CMD_SHIFT);

        cmd_addr = (void __iomem *)cmd_phase_addr;

        /* Get the data phase address */
        end_cmd_valid = 0;

        data_phase_addr = (unsigned long)xnand->nand_base       |
                        (0x0 << CLEAR_CS_SHIFT)                         |
                        (end_cmd_valid << END_CMD_VALID_SHIFT)          |
                        (DATA_PHASE)                                    |
                        (end_cmd << END_CMD_SHIFT)                      |
                        (0x0 << ECC_LAST_SHIFT);

        chip->IO_ADDR_R = (void  __iomem *)data_phase_addr;
        chip->IO_ADDR_W = chip->IO_ADDR_R;

        /* Command phase AXI Read & Write */
        if (column != -1 && page_addr != -1) {
                /* Adjust columns for 16 bit bus width */
                if (chip->options & NAND_BUSWIDTH_16)
                        column >>= 1;
                cmd_data = column;
                if (mtd->writesize > ZYNQ_NAND_ECC_SIZE) {
                        cmd_data |= page_addr << 16;
                        /* Another address cycle for devices > 128MiB */
                        if (chip->chipsize > (128 << 20)) {
                                writel(cmd_data, cmd_addr);
                                cmd_data = (page_addr >> 16);
                        }
                } else {
                        cmd_data |= page_addr << 8;
                }
        } else if (page_addr != -1)  { /* Erase */
                cmd_data = page_addr;
        } else if (column != -1) { /* Change read/write column, read id etc */
                /* Adjust columns for 16 bit bus width */
                if ((chip->options & NAND_BUSWIDTH_16) &&
                    ((command == NAND_CMD_READ0) ||
                     (command == NAND_CMD_SEQIN) ||
                     (command == NAND_CMD_RNDOUT) ||
                     (command == NAND_CMD_RNDIN)))
                        column >>= 1;
                cmd_data = column;
        }

        writel(cmd_data, cmd_addr);

        if (curr_cmd->end_cmd_valid) {
                xnand->end_cmd = curr_cmd->end_cmd;
                xnand->end_cmd_pending = 1;
        }

        ndelay(100);

        if ((command == NAND_CMD_READ0) ||
            (command == NAND_CMD_RESET) ||
            (command == NAND_CMD_PARAM) ||
            (command == NAND_CMD_GET_FEATURES))
                /* wait until command is processed */
                nand_wait_ready(mtd);
}

/*
 * zynq_nand_read_buf - read chip data into buffer
 * @mtd:        MTD device structure
 * @buf:        buffer to store date
 * @len:        number of bytes to read
 */
static void zynq_nand_read_buf(struct mtd_info *mtd, u8 *buf, int len)
{
        struct nand_chip *chip = mtd->priv;

        /* Make sure that buf is 32 bit aligned */
        if (((unsigned long)buf & 0x3) != 0) {
                if (((unsigned long)buf & 0x1) != 0) {
                        if (len) {
                                *buf = readb(chip->IO_ADDR_R);
                                buf += 1;
                                len--;
                        }
                }

                if (((unsigned long)buf & 0x3) != 0) {
                        if (len >= 2) {
                                *(u16 *)buf = readw(chip->IO_ADDR_R);
                                buf += 2;
                                len -= 2;
                        }
                }
        }

        /* copy aligned data */
        while (len >= 4) {
                *(u32 *)buf = readl(chip->IO_ADDR_R);
                buf += 4;
                len -= 4;
        }

        /* mop up any remaining bytes */
        if (len) {
                if (len >= 2) {
                        *(u16 *)buf = readw(chip->IO_ADDR_R);
                        buf += 2;
                        len -= 2;
                }
                if (len)
                        *buf = readb(chip->IO_ADDR_R);
        }
}

/*
 * zynq_nand_write_buf - write buffer to chip
 * @mtd:        MTD device structure
 * @buf:        data buffer
 * @len:        number of bytes to write
 */
static void zynq_nand_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
{
        struct nand_chip *chip = mtd->priv;
        const u32 *nand = chip->IO_ADDR_W;

        /* Make sure that buf is 32 bit aligned */
        if (((unsigned long)buf & 0x3) != 0) {
                if (((unsigned long)buf & 0x1) != 0) {
                        if (len) {
                                writeb(*buf, nand);
                                buf += 1;
                                len--;
                        }
                }

                if (((unsigned long)buf & 0x3) != 0) {
                        if (len >= 2) {
                                writew(*(u16 *)buf, nand);
                                buf += 2;
                                len -= 2;
                        }
                }
        }

        /* copy aligned data */
        while (len >= 4) {
                writel(*(u32 *)buf, nand);
                buf += 4;
                len -= 4;
        }

        /* mop up any remaining bytes */
        if (len) {
                if (len >= 2) {

                        writew(*(u16 *)buf, nand);
                        buf += 2;
                        len -= 2;
                }

                if (len)
                        writeb(*buf, nand);
        }
}

/*
 * zynq_nand_device_ready - Check device ready/busy line
 * @mtd:        Pointer to the mtd_info structure
 *
 * returns:     0 on busy or 1 on ready state
 */
static int zynq_nand_device_ready(struct mtd_info *mtd)
{
        u32 csr_val;

        csr_val = readl(&zynq_nand_smc_base->csr);
        /* Check the raw_int_status1 bit */
        if (csr_val & ZYNQ_MEMC_SR_RAW_INT_ST1) {
                /* Clear the interrupt condition */
                writel(ZYNQ_MEMC_SR_INT_ST1, &zynq_nand_smc_base->cfr);
                return 1;
        }

        return 0;
}

static int zynq_nand_check_is_16bit_bw_flash(void)
{
        int is_16bit_bw = NAND_BW_UNKNOWN;
        int mio_num_8bit = 0, mio_num_16bit = 0;

        mio_num_8bit = zynq_slcr_get_mio_pin_status("nand8");
        if (mio_num_8bit == ZYNQ_NAND_MIO_NUM_NAND_8BIT)
                is_16bit_bw = NAND_BW_8BIT;

        mio_num_16bit = zynq_slcr_get_mio_pin_status("nand16");
        if (mio_num_8bit == ZYNQ_NAND_MIO_NUM_NAND_8BIT &&
            mio_num_16bit == ZYNQ_NAND_MIO_NUM_NAND_16BIT)
                is_16bit_bw = NAND_BW_16BIT;

        return is_16bit_bw;
}

static int zynq_nand_init(struct nand_chip *nand_chip, int devnum)
{
        struct zynq_nand_info *xnand;
        struct mtd_info *mtd;
        unsigned long ecc_page_size;
        u8 maf_id, dev_id, i;
        u8 get_feature[4];
        u8 set_feature[4] = {ONDIE_ECC_FEATURE_ENABLE, 0x00, 0x00, 0x00};
        unsigned long ecc_cfg;
        int ondie_ecc_enabled = 0;
        int err = -1;
        int is_16bit_bw;

        xnand = calloc(1, sizeof(struct zynq_nand_info));
        if (!xnand) {
                printf("%s: failed to allocate\n", __func__);
                goto fail;
        }

        xnand->nand_base = (void __iomem *)ZYNQ_NAND_BASEADDR;
        mtd = nand_to_mtd(nand_chip);

        nand_chip->priv = xnand;
        mtd->priv = nand_chip;

        /* Set address of NAND IO lines */
        nand_chip->IO_ADDR_R = xnand->nand_base;
        nand_chip->IO_ADDR_W = xnand->nand_base;

        /* Set the driver entry points for MTD */
        nand_chip->cmdfunc = zynq_nand_cmd_function;
        nand_chip->dev_ready = zynq_nand_device_ready;
        nand_chip->select_chip = zynq_nand_select_chip;

        /* If we don't set this delay driver sets 20us by default */
        nand_chip->chip_delay = 30;

        /* Buffer read/write routines */
        nand_chip->read_buf = zynq_nand_read_buf;
        nand_chip->write_buf = zynq_nand_write_buf;

        is_16bit_bw = zynq_nand_check_is_16bit_bw_flash();
        if (is_16bit_bw == NAND_BW_UNKNOWN) {
                printf("%s: Unable detect NAND based on MIO settings\n",
                       __func__);
                goto fail;
        }

        if (is_16bit_bw == NAND_BW_16BIT)
                nand_chip->options = NAND_BUSWIDTH_16;

        nand_chip->bbt_options = NAND_BBT_USE_FLASH;

        /* Initialize the NAND flash interface on NAND controller */
        if (zynq_nand_init_nand_flash(nand_chip->options) < 0) {
                printf("%s: nand flash init failed\n", __func__);
                goto fail;
        }

        /* first scan to find the device and get the page size */
        if (nand_scan_ident(mtd, 1, NULL)) {
                printf("%s: nand_scan_ident failed\n", __func__);
                goto fail;
        }
        /* Send the command for reading device ID */
        nand_chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);
        nand_chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);

        /* Read manufacturer and device IDs */
        maf_id = nand_chip->read_byte(mtd);
        dev_id = nand_chip->read_byte(mtd);

        if ((maf_id == 0x2c) && ((dev_id == 0xf1) ||
                                 (dev_id == 0xa1) || (dev_id == 0xb1) ||
                                 (dev_id == 0xaa) || (dev_id == 0xba) ||
                                 (dev_id == 0xda) || (dev_id == 0xca) ||
                                 (dev_id == 0xac) || (dev_id == 0xbc) ||
                                 (dev_id == 0xdc) || (dev_id == 0xcc) ||
                                 (dev_id == 0xa3) || (dev_id == 0xb3) ||
                                 (dev_id == 0xd3) || (dev_id == 0xc3))) {
                nand_chip->cmdfunc(mtd, NAND_CMD_SET_FEATURES,
                                                ONDIE_ECC_FEATURE_ADDR, -1);
                for (i = 0; i < 4; i++)
                        writeb(set_feature[i], nand_chip->IO_ADDR_W);

                /* Wait for 1us after writing data with SET_FEATURES command */
                ndelay(1000);

                nand_chip->cmdfunc(mtd, NAND_CMD_GET_FEATURES,
                                                ONDIE_ECC_FEATURE_ADDR, -1);
                nand_chip->read_buf(mtd, get_feature, 4);

                if (get_feature[0] & ONDIE_ECC_FEATURE_ENABLE) {
                        debug("%s: OnDie ECC flash\n", __func__);
                        ondie_ecc_enabled = 1;
                } else {
                        printf("%s: Unable to detect OnDie ECC\n", __func__);
                }
        }

        if (ondie_ecc_enabled) {
                /* Bypass the controller ECC block */
                ecc_cfg = readl(&zynq_nand_smc_base->emcr);
                ecc_cfg &= ~ZYNQ_MEMC_NAND_ECC_MODE_MASK;
                writel(ecc_cfg, &zynq_nand_smc_base->emcr);

                /* The software ECC routines won't work
                 * with the SMC controller
                 */
                nand_chip->ecc.mode = NAND_ECC_HW;
                nand_chip->ecc.strength = 1;
                nand_chip->ecc.read_page = zynq_nand_read_page_raw_nooob;
                nand_chip->ecc.read_subpage = zynq_nand_read_subpage_raw;
                nand_chip->ecc.write_page = zynq_nand_write_page_raw;
                nand_chip->ecc.read_page_raw = zynq_nand_read_page_raw;
                nand_chip->ecc.write_page_raw = zynq_nand_write_page_raw;
                nand_chip->ecc.read_oob = zynq_nand_read_oob;
                nand_chip->ecc.write_oob = zynq_nand_write_oob;
                nand_chip->ecc.size = mtd->writesize;
                nand_chip->ecc.bytes = 0;

                /* NAND with on-die ECC supports subpage reads */
                nand_chip->options |= NAND_SUBPAGE_READ;

                /* On-Die ECC spare bytes offset 8 is used for ECC codes */
                if (ondie_ecc_enabled) {
                        nand_chip->ecc.layout = &ondie_nand_oob_64;
                        /* Use the BBT pattern descriptors */
                        nand_chip->bbt_td = &bbt_main_descr;
                        nand_chip->bbt_md = &bbt_mirror_descr;
                }
        } else {
                /* Hardware ECC generates 3 bytes ECC code for each 512 bytes */
                nand_chip->ecc.mode = NAND_ECC_HW;
                nand_chip->ecc.strength = 1;
                nand_chip->ecc.size = ZYNQ_NAND_ECC_SIZE;
                nand_chip->ecc.bytes = 3;
                nand_chip->ecc.calculate = zynq_nand_calculate_hwecc;
                nand_chip->ecc.correct = zynq_nand_correct_data;
                nand_chip->ecc.hwctl = NULL;
                nand_chip->ecc.read_page = zynq_nand_read_page_hwecc;
                nand_chip->ecc.write_page = zynq_nand_write_page_hwecc;
                nand_chip->ecc.read_page_raw = zynq_nand_read_page_raw;
                nand_chip->ecc.write_page_raw = zynq_nand_write_page_raw;
                nand_chip->ecc.read_oob = zynq_nand_read_oob;
                nand_chip->ecc.write_oob = zynq_nand_write_oob;

                switch (mtd->writesize) {
                case 512:
                        ecc_page_size = 0x1;
                        /* Set the ECC memory config register */
                        writel((ZYNQ_NAND_ECC_CONFIG | ecc_page_size),
                               &zynq_nand_smc_base->emcr);
                        break;
                case 1024:
                        ecc_page_size = 0x2;
                        /* Set the ECC memory config register */
                        writel((ZYNQ_NAND_ECC_CONFIG | ecc_page_size),
                               &zynq_nand_smc_base->emcr);
                        break;
                case 2048:
                        ecc_page_size = 0x3;
                        /* Set the ECC memory config register */
                        writel((ZYNQ_NAND_ECC_CONFIG | ecc_page_size),
                               &zynq_nand_smc_base->emcr);
                        break;
                default:
                        nand_chip->ecc.mode = NAND_ECC_SOFT;
                        nand_chip->ecc.calculate = nand_calculate_ecc;
                        nand_chip->ecc.correct = nand_correct_data;
                        nand_chip->ecc.read_page = zynq_nand_read_page_swecc;
                        nand_chip->ecc.write_page = zynq_nand_write_page_swecc;
                        nand_chip->ecc.size = 256;
                        break;
                }

                if (mtd->oobsize == 16)
                        nand_chip->ecc.layout = &nand_oob_16;
                else if (mtd->oobsize == 64)
                        nand_chip->ecc.layout = &nand_oob_64;
                else
                        printf("%s: No oob layout found\n", __func__);
        }

        /* Second phase scan */
        if (nand_scan_tail(mtd)) {
                printf("%s: nand_scan_tail failed\n", __func__);
                goto fail;
        }
        if (nand_register(devnum, mtd))
                goto fail;
        return 0;
fail:
        free(xnand);
        return err;
}

static struct nand_chip nand_chip[CONFIG_SYS_MAX_NAND_DEVICE];

void board_nand_init(void)
{
        struct nand_chip *nand = &nand_chip[0];

        if (zynq_nand_init(nand, 0))
                puts("ZYNQ NAND init failed\n");
}