[openocd.git] / src / flash / davinci_nand.c

/***************************************************************************
 *   Copyright (C) 2009 by David Brownell                                  *
 *                                                                         *
 *   This program 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.                                   *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/

/*
 * DaVinci family NAND controller support for OpenOCD.
 *
 * This driver uses hardware ECC (1-bit or 4-bit) unless
 * the chip is accessed in "raw" mode.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "arm_nandio.h"


enum ecc {
        HWECC1,         /* all controllers support 1-bit ECC */
        HWECC4,         /* newer chips also have 4-bit ECC hardware */
        HWECC4_INFIX,   /* avoid this layout, except maybe for boot code */
};

struct davinci_nand {
        target_t        *target;

        uint8_t         chipsel;        /* chipselect 0..3 == CS2..CS5 */
        uint8_t         eccmode;

        /* Async EMIF controller base */
        uint32_t                aemif;

        /* NAND chip addresses */
        uint32_t                data;           /* without CLE or ALE */
        uint32_t                cmd;            /* with CLE */
        uint32_t                addr;           /* with ALE */

        /* write acceleration */
        struct arm_nand_data    io;

        /* page i/o for the relevant flavor of hardware ECC */
        int (*read_page)(struct nand_device_s *nand, uint32_t page,
                        uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size);
        int (*write_page)(struct nand_device_s *nand, uint32_t page,
                        uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size);
};

#define NANDFCR         0x60            /* flash control register */
#define NANDFSR         0x64            /* flash status register */
#define NANDFECC        0x70            /* 1-bit ECC data, CS0, 1st of 4 */
#define NAND4BITECCLOAD 0xbc            /* 4-bit ECC, load saved values */
#define NAND4BITECC     0xc0            /* 4-bit ECC data, 1st of 4 */
#define NANDERRADDR     0xd0            /* 4-bit ECC err addr, 1st of 2 */
#define NANDERRVAL      0xd8            /* 4-bit ECC err value, 1st of 2 */

static int halted(target_t *target, const char *label)
{
        if (target->state == TARGET_HALTED)
                return true;

        LOG_ERROR("Target must be halted to use NAND controller (%s)", label);
        return false;
}

static int davinci_register_commands(struct command_context_s *cmd_ctx)
{
        return ERROR_OK;
}

static int davinci_init(struct nand_device_s *nand)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;
        uint32_t nandfcr;

        if (!halted(target, "init"))
                return ERROR_NAND_OPERATION_FAILED;

        /* We require something else to have configured AEMIF to talk
         * to NAND chip in this range (including timings and width).
         */
        target_read_u32(target, info->aemif + NANDFCR, &nandfcr);
        if (!(nandfcr & (1 << info->chipsel))) {
                LOG_ERROR("chip address %08" PRIx32 " not NAND-enabled?", info->data);
                return ERROR_NAND_OPERATION_FAILED;
        }

        /* REVISIT verify:  AxCR must be in 8-bit mode, since that's all we
         * tested.  16 bit support should work too; but not with 4-bit ECC.
         */

        return ERROR_OK;
}

static int davinci_reset(struct nand_device_s *nand)
{
        return ERROR_OK;
}

static int davinci_nand_ready(struct nand_device_s *nand, int timeout)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;
        uint32_t nandfsr;

        /* NOTE: return code is zero/error, else success; not ERROR_* */

        if (!halted(target, "ready"))
                return 0;

        do {
                target_read_u32(target, info->aemif + NANDFSR, &nandfsr);

                if (nandfsr & 0x01)
                        return 1;

                alive_sleep(1);
        } while (timeout-- > 0);

        return 0;
}

static int davinci_command(struct nand_device_s *nand, uint8_t command)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;

        if (!halted(target, "command"))
                return ERROR_NAND_OPERATION_FAILED;

        target_write_u8(target, info->cmd, command);
        return ERROR_OK;
}

static int davinci_address(struct nand_device_s *nand, uint8_t address)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;

        if (!halted(target, "address"))
                return ERROR_NAND_OPERATION_FAILED;

        target_write_u8(target, info->addr, address);
        return ERROR_OK;
}

static int davinci_write_data(struct nand_device_s *nand, uint16_t data)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;

        if (!halted(target, "write_data"))
                return ERROR_NAND_OPERATION_FAILED;

        target_write_u8(target, info->data, data);
        return ERROR_OK;
}

static int davinci_read_data(struct nand_device_s *nand, void *data)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;

        if (!halted(target, "read_data"))
                return ERROR_NAND_OPERATION_FAILED;

        target_read_u8(target, info->data, data);
        return ERROR_OK;
}

/* REVISIT a bit of native code should let block reads be MUCH faster */

static int davinci_read_block_data(struct nand_device_s *nand,
                uint8_t *data, int data_size)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;
        uint32_t nfdata = info->data;
        uint32_t tmp;

        if (!halted(target, "read_block"))
                return ERROR_NAND_OPERATION_FAILED;

        while (data_size >= 4) {
                target_read_u32(target, nfdata, &tmp);

                data[0] = tmp;
                data[1] = tmp >> 8;
                data[2] = tmp >> 16;
                data[3] = tmp >> 24;

                data_size -= 4;
                data += 4;
        }

        while (data_size > 0) {
                target_read_u8(target, nfdata, data);

                data_size -= 1;
                data += 1;
        }

        return ERROR_OK;
}

static int davinci_write_block_data(struct nand_device_s *nand,
                uint8_t *data, int data_size)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;
        uint32_t nfdata = info->data;
        uint32_t tmp;
        int status;

        if (!halted(target, "write_block"))
                return ERROR_NAND_OPERATION_FAILED;

        /* try the fast way first */
        status = arm_nandwrite(&info->io, data, data_size);
        if (status != ERROR_NAND_NO_BUFFER)
                return status;

        /* else do it slowly */
        while (data_size >= 4) {
                tmp = le_to_h_u32(data);
                target_write_u32(target, nfdata, tmp);

                data_size -= 4;
                data += 4;
        }

        while (data_size > 0) {
                target_write_u8(target, nfdata, *data);

                data_size -= 1;
                data += 1;
        }

        return ERROR_OK;
}

static int davinci_write_page(struct nand_device_s *nand, uint32_t page,
                uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
{
        struct davinci_nand *info = nand->controller_priv;
        uint8_t *ooballoc = NULL;
        int status;

        if (!nand->device)
                return ERROR_NAND_DEVICE_NOT_PROBED;
        if (!halted(info->target, "write_page"))
                return ERROR_NAND_OPERATION_FAILED;

        /* Always write both data and OOB ... we are not "raw" I/O! */
        if (!data) {
                LOG_ERROR("Missing NAND data; try 'nand raw_access enable'\n");
                return ERROR_NAND_OPERATION_FAILED;
        }

        /* If we're not given OOB, write 0xff where we don't write ECC codes. */
        switch (nand->page_size) {
        case 512:
                oob_size = 16;
                break;
        case 2048:
                oob_size = 64;
                break;
        case 4096:
                oob_size = 128;
                break;
        default:
                return ERROR_NAND_OPERATION_FAILED;
        }
        if (!oob) {
                ooballoc = malloc(oob_size);
                if (!ooballoc)
                        return ERROR_NAND_OPERATION_FAILED;
                oob = ooballoc;
                memset(oob, 0x0ff, oob_size);
        }

        /* REVISIT avoid wasting SRAM:  unless nand->use_raw is set,
         * use 512 byte chunks.  Read side support will often want
         * to include oob_size ...
         */
        info->io.chunk_size = nand->page_size;

        status = info->write_page(nand, page, data, data_size, oob, oob_size);
        free(ooballoc);
        return status;
}

static int davinci_read_page(struct nand_device_s *nand, uint32_t page,
                uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
{
        struct davinci_nand *info = nand->controller_priv;

        if (!nand->device)
                return ERROR_NAND_DEVICE_NOT_PROBED;
        if (!halted(info->target, "read_page"))
                return ERROR_NAND_OPERATION_FAILED;

        return info->read_page(nand, page, data, data_size, oob, oob_size);
}

static void davinci_write_pagecmd(struct nand_device_s *nand, uint8_t cmd, uint32_t page)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;
        int page3 = nand->address_cycles - (nand->page_size == 512);

        /* write command ({page,otp}x{read,program} */
        target_write_u8(target, info->cmd, cmd);

        /* column address (beginning-of-page) */
        target_write_u8(target, info->addr, 0);
        if (nand->page_size > 512)
                target_write_u8(target, info->addr, 0);

        /* page address */
        target_write_u8(target, info->addr, page);
        target_write_u8(target, info->addr, page >> 8);
        if (page3)
                target_write_u8(target, info->addr, page >> 16);
        if (page3 == 2)
                target_write_u8(target, info->addr, page >> 24);
}

static int davinci_writepage_tail(struct nand_device_s *nand,
                uint8_t *oob, uint32_t oob_size)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;
        uint8_t status;

        if (oob_size)
                davinci_write_block_data(nand, oob, oob_size);

        /* non-cachemode page program */
        target_write_u8(target, info->cmd, NAND_CMD_PAGEPROG);

        if (!davinci_nand_ready(nand, 100))
                return ERROR_NAND_OPERATION_TIMEOUT;

        if (nand_read_status(nand, &status) != ERROR_OK) {
                LOG_ERROR("couldn't read status");
                return ERROR_NAND_OPERATION_FAILED;
        }

        if (status & NAND_STATUS_FAIL) {
                LOG_ERROR("write operation failed, status: 0x%02x", status);
                return ERROR_NAND_OPERATION_FAILED;
        }

        return ERROR_OK;
}

/*
 * All DaVinci family chips support 1-bit ECC on a per-chipselect basis.
 */
static int davinci_write_page_ecc1(struct nand_device_s *nand, uint32_t page,
                uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
{
        unsigned oob_offset;
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;
        const uint32_t fcr_addr = info->aemif + NANDFCR;
        const uint32_t ecc1_addr = info->aemif + NANDFECC + (4 * info->chipsel);
        uint32_t fcr, ecc1;

        /* Write contiguous ECC bytes starting at specified offset.
         * NOTE: Linux reserves twice as many bytes as we need; and
         * for 16-bit OOB, those extra bytes are discontiguous.
         */
        switch (nand->page_size) {
        case 512:
                oob_offset = 0;
                break;
        case 2048:
                oob_offset = 40;
                break;
        default:
                oob_offset = 80;
                break;
        }

        davinci_write_pagecmd(nand, NAND_CMD_SEQIN, page);

        /* scrub any old ECC state */
        target_read_u32(target, ecc1_addr, &ecc1);

        target_read_u32(target, fcr_addr, &fcr);
        fcr |= 1 << (8 + info->chipsel);

        do {
                /* set "start csX 1bit ecc" bit */
                target_write_u32(target, fcr_addr, fcr);

                /* write 512 bytes */
                davinci_write_block_data(nand, data, 512);
                data += 512;
                data_size -= 512;

                /* read the ecc, pack to 3 bytes, and invert so the ecc
                 * in an erased block is correct
                 */
                target_read_u32(target, ecc1_addr, &ecc1);
                ecc1 = (ecc1 & 0x0fff) | ((ecc1 & 0x0fff0000) >> 4);
                ecc1 = ~ecc1;

                /* save correct ECC code into oob data */
                oob[oob_offset++] = (uint8_t)(ecc1);
                oob[oob_offset++] = (uint8_t)(ecc1 >> 8);
                oob[oob_offset++] = (uint8_t)(ecc1 >> 16);

        } while (data_size);

        /* write OOB into spare area */
        return davinci_writepage_tail(nand, oob, oob_size);
}

/*
 * Preferred "new style" ECC layout for use with 4-bit ECC.  This somewhat
 * slows down large page reads done with error correction (since the OOB
 * is read first, so its ECC data can be used incrementally), but the
 * manufacturer bad block markers are safe.  Contrast:  old "infix" style.
 */
static int davinci_write_page_ecc4(struct nand_device_s *nand, uint32_t page,
                uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
{
        static const uint8_t ecc512[] = {
                0, 1, 2, 3, 4, /* 5== mfr badblock */
                6, 7, /* 8..12 for BBT or JFFS2 */ 13, 14, 15,
        };
        static const uint8_t ecc2048[] = {
                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,
        };
        static const uint8_t ecc4096[] = {
                 48,  49,  50,  51,  52,  53,  54,  55,  56,  57,
                 58,  59,  60,  61,  62,  63,  64,  65,  66,  67,
                 68,  69,  70,  71,  72,  73,  74,  75,  76,  77,
                 78,  79,  80,  81,  82,  83,  84,  85,  86,  87,
                 88,  89,  90,  91,  92,  93,  94,  95,  96,  97,
                 98,  99, 100, 101, 102, 103, 104, 105, 106, 107,
                108, 109, 110, 111, 112, 113, 114, 115, 116, 117,
                118, 119, 120, 121, 122, 123, 124, 125, 126, 127,
        };

        struct davinci_nand *info = nand->controller_priv;
        const uint8_t *l;
        target_t *target = info->target;
        const uint32_t fcr_addr = info->aemif + NANDFCR;
        const uint32_t ecc4_addr = info->aemif + NAND4BITECC;
        uint32_t fcr, ecc4;

        /* Use the same ECC layout Linux uses.  For small page chips
         * it's a bit cramped.
         *
         * NOTE:  at this writing, 4KB pages have issues in Linux
         * because they need more than 64 bytes of ECC data, which
         * the standard ECC logic can't handle.
         */
        switch (nand->page_size) {
        case 512:
                l = ecc512;
                break;
        case 2048:
                l = ecc2048;
                break;
        default:
                l = ecc4096;
                break;
        }

        davinci_write_pagecmd(nand, NAND_CMD_SEQIN, page);

        /* scrub any old ECC state */
        target_read_u32(target, info->aemif + NANDERRVAL, &ecc4);

        target_read_u32(target, fcr_addr, &fcr);
        fcr &= ~(0x03 << 4);
        fcr |= (1 << 12) | (info->chipsel << 4);

        do {
                uint32_t raw_ecc[4], *p;
                int i;

                /* start 4bit ecc on csX */
                target_write_u32(target, fcr_addr, fcr);

                /* write 512 bytes */
                davinci_write_block_data(nand, data, 512);
                data += 512;
                data_size -= 512;

                /* read the ecc, then save it into 10 bytes in the oob */
                for (i = 0; i < 4; i++) {
                        target_read_u32(target, ecc4_addr + 4 * i, &raw_ecc[i]);
                        raw_ecc[i] &= 0x03ff03ff;
                }
                for (i = 0, p = raw_ecc; i < 2; i++, p += 2) {
                        oob[*l++] =   p[0]        & 0xff;
                        oob[*l++] = ((p[0] >>  8) & 0x03) | ((p[0] >> 14) & 0xfc);
                        oob[*l++] = ((p[0] >> 22) & 0x0f) | ((p[1] <<  4) & 0xf0);
                        oob[*l++] = ((p[1] >>  4) & 0x3f) | ((p[1] >> 10) & 0xc0);
                        oob[*l++] =  (p[1] >> 18) & 0xff;
                }

        } while (data_size);

        /* write OOB into spare area */
        return davinci_writepage_tail(nand, oob, oob_size);
}

/*
 * "Infix" OOB ... like Linux ECC_HW_SYNDROME.  Avoided because it trashes
 * manufacturer bad block markers, except on small page chips.  Once you
 * write to a page using this scheme, you need specialized code to update
 * it (code which ignores now-invalid bad block markers).
 *
 * This is needed *only* to support older firmware.  Older ROM Boot Loaders
 * need it to read their second stage loader (UBL) into SRAM, but from then
 * on the whole system can use the cleaner non-infix layouts.  Systems with
 * older second stage loaders (ABL/U-Boot, etc) or other system software
 * (MVL 4.x/5.x kernels, filesystems, etc) may need it more generally.
 */
static int davinci_write_page_ecc4infix(struct nand_device_s *nand, uint32_t page,
                uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
{
        struct davinci_nand *info = nand->controller_priv;
        target_t *target = info->target;
        const uint32_t fcr_addr = info->aemif + NANDFCR;
        const uint32_t ecc4_addr = info->aemif + NAND4BITECC;
        uint32_t fcr, ecc4;

        davinci_write_pagecmd(nand, NAND_CMD_SEQIN, page);

        /* scrub any old ECC state */
        target_read_u32(target, info->aemif + NANDERRVAL, &ecc4);

        target_read_u32(target, fcr_addr, &fcr);
        fcr &= ~(0x03 << 4);
        fcr |= (1 << 12) | (info->chipsel << 4);

        do {
                uint32_t raw_ecc[4], *p;
                uint8_t *l;
                int i;

                /* start 4bit ecc on csX */
                target_write_u32(target, fcr_addr, fcr);

                /* write 512 bytes */
                davinci_write_block_data(nand, data, 512);
                data += 512;
                data_size -= 512;

                /* read the ecc */
                for (i = 0; i < 4; i++) {
                        target_read_u32(target, ecc4_addr + 4 * i, &raw_ecc[i]);
                        raw_ecc[i] &= 0x03ff03ff;
                }

                /* skip 6 bytes of prepad, then pack 10 packed ecc bytes */
                for (i = 0, l = oob + 6, p = raw_ecc; i < 2; i++, p += 2) {
                        *l++ =   p[0]        & 0xff;
                        *l++ = ((p[0] >>  8) & 0x03) | ((p[0] >> 14) & 0xfc);
                        *l++ = ((p[0] >> 22) & 0x0f) | ((p[1] <<  4) & 0xf0);
                        *l++ = ((p[1] >>  4) & 0x3f) | ((p[1] >> 10) & 0xc0);
                        *l++ =  (p[1] >> 18) & 0xff;
                }

                /* write this "out-of-band" data -- infix */
                davinci_write_block_data(nand, oob, 16);
                oob += 16;
                oob_size -= 16;

        } while (data_size);

        /* the last data and OOB writes included the spare area */
        return davinci_writepage_tail(nand, NULL, 0);
}

static int davinci_read_page_ecc4infix(struct nand_device_s *nand, uint32_t page,
                uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
{
        davinci_write_pagecmd(nand, NAND_CMD_READ0, page);

        /* large page devices need a start command */
        if (nand->page_size > 512)
                davinci_command(nand, NAND_CMD_READSTART);

        if (!davinci_nand_ready(nand, 100))
                return ERROR_NAND_OPERATION_TIMEOUT;

        /* NOTE:  not bothering to compute and use ECC data for now */

        do {
                /* write 512 bytes */
                davinci_read_block_data(nand, data, 512);
                data += 512;
                data_size -= 512;

                /* read this "out-of-band" data -- infix */
                davinci_read_block_data(nand, oob, 16);
                oob += 16;
                oob_size -= 16;
        } while (data_size);

        return ERROR_OK;
}

NAND_DEVICE_COMMAND_HANDLER(davinci_nand_device_command)
{
        struct davinci_nand *info;
        target_t *target;
        unsigned long chip, aemif;
        enum ecc eccmode;
        int chipsel;

        /* arguments:
         *  - "davinci"
         *  - target
         *  - nand chip address
         *  - ecc mode
         *  - aemif address
         * Plus someday, optionally, ALE and CLE masks.
         */
        if (argc < 5) {
                LOG_ERROR("parameters: %s target "
                                "chip_addr hwecc_mode aemif_addr",
                                args[0]);
                goto fail;
        }

        target = get_target(args[1]);
        if (!target) {
                LOG_ERROR("invalid target %s", args[1]);
                goto fail;
        }

        COMMAND_PARSE_NUMBER(ulong, args[2], chip);
        if (chip == 0) {
                LOG_ERROR("Invalid NAND chip address %s", args[2]);
                goto fail;
        }

        if (strcmp(args[3], "hwecc1") == 0)
                eccmode = HWECC1;
        else if (strcmp(args[3], "hwecc4") == 0)
                eccmode = HWECC4;
        else if (strcmp(args[3], "hwecc4_infix") == 0)
                eccmode = HWECC4_INFIX;
        else {
                LOG_ERROR("Invalid ecc mode %s", args[3]);
                goto fail;
        }

        COMMAND_PARSE_NUMBER(ulong, args[4], aemif);
        if (aemif == 0) {
                LOG_ERROR("Invalid AEMIF controller address %s", args[4]);
                goto fail;
        }

        /* REVISIT what we'd *like* to do is look up valid ranges using
         * target-specific declarations, and not even need to pass the
         * AEMIF controller address.
         */
        if (aemif == 0x01e00000                 /* dm6446, dm357 */
                        || aemif == 0x01e10000  /* dm335, dm355 */
                        || aemif == 0x01d10000  /* dm365 */
                        ) {
                if (chip < 0x02000000 || chip >= 0x0a000000) {
                        LOG_ERROR("NAND address %08lx out of range?", chip);
                        goto fail;
                }
                chipsel = (chip - 0x02000000) >> 25;
        } else {
                LOG_ERROR("unrecognized AEMIF controller address %08lx", aemif);
                goto fail;
        }

        info = calloc(1, sizeof *info);
        if (info == NULL)
                goto fail;

        info->target = target;
        info->eccmode = eccmode;
        info->chipsel = chipsel;
        info->aemif = aemif;
        info->data = chip;
        info->cmd = chip | 0x10;
        info->addr = chip | 0x08;

        nand->controller_priv = info;

        info->io.target = target;
        info->io.data = info->data;

        /* NOTE:  for now we don't do any error correction on read.
         * Nothing else in OpenOCD currently corrects read errors,
         * and in any case it's *writing* that we care most about.
         */
        info->read_page = nand_read_page_raw;

        switch (eccmode) {
        case HWECC1:
                /* ECC_HW, 1-bit corrections, 3 bytes ECC per 512 data bytes */
                info->write_page = davinci_write_page_ecc1;
                break;
        case HWECC4:
                /* ECC_HW, 4-bit corrections, 10 bytes ECC per 512 data bytes */
                info->write_page = davinci_write_page_ecc4;
                break;
        case HWECC4_INFIX:
                /* Same 4-bit ECC HW, with problematic page/ecc layout */
                info->read_page = davinci_read_page_ecc4infix;
                info->write_page = davinci_write_page_ecc4infix;
                break;
        }

        return ERROR_OK;

fail:
        return ERROR_NAND_OPERATION_FAILED;
}

nand_flash_controller_t davinci_nand_controller = {
        .name                   = "davinci",
        .nand_device_command    = davinci_nand_device_command,
        .register_commands      = davinci_register_commands,
        .init                   = davinci_init,
        .reset                  = davinci_reset,
        .command                = davinci_command,
        .address                = davinci_address,
        .write_data             = davinci_write_data,
        .read_data              = davinci_read_data,
        .write_page             = davinci_write_page,
        .read_page              = davinci_read_page,
        .write_block_data       = davinci_write_block_data,
        .read_block_data        = davinci_read_block_data,
        .nand_ready             = davinci_nand_ready,
};