davinci.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2009 by David Brownell                                  *
 ***************************************************************************/
 
/*
 * 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 "imp.h"
#include "arm_io.h"
#include <target/target.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 {
    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 *nand, uint32_t page,
             uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size);
    int (*write_page)(struct nand_device *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(struct target *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_init(struct nand_device *nand)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *nand)
{
    return ERROR_OK;
}
 
static int davinci_nand_ready(struct nand_device *nand, int timeout)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *nand, uint8_t command)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *nand, uint8_t address)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *nand, uint16_t data)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *nand, void *data)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *nand,
    uint8_t *data, int data_size)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *nand,
    uint8_t *data, int data_size)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *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(nand->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'");
        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 *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(nand->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 *nand, uint8_t cmd, uint32_t page)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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_seek_column(struct nand_device *nand, uint16_t column)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->target;
 
    /* Random read, we must have issued a page read already */
    target_write_u8(target, info->cmd, NAND_CMD_RNDOUT);
 
    target_write_u8(target, info->addr, column);
 
    if (nand->page_size > 512) {
        target_write_u8(target, info->addr, column >> 8);
        target_write_u8(target, info->cmd, NAND_CMD_RNDOUTSTART);
    }
 
    if (!davinci_nand_ready(nand, 100))
        return ERROR_NAND_OPERATION_TIMEOUT;
 
    return ERROR_OK;
}
 
static int davinci_writepage_tail(struct nand_device *nand,
    uint8_t *oob, uint32_t oob_size)
{
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *nand, uint32_t page,
    uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
{
    unsigned int oob_offset;
    struct davinci_nand *info = nand->controller_priv;
    struct target *target = nand->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 *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;
    struct target *target = nand->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 *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;
    struct target *target = nand->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;
    } 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 *nand, uint32_t page,
    uint8_t *data, uint32_t data_size, uint8_t *oob, uint32_t oob_size)
{
    int read_size;
    int want_col, at_col;
    int ret;
 
    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 */
 
    want_col = 0;
    at_col = 0;
    while ((data && data_size) || (oob && oob_size)) {
 
        if (data && data_size) {
            if (want_col != at_col) {
                /* Reads are slow, so seek past them when we can */
                ret  = davinci_seek_column(nand, want_col);
                if (ret != ERROR_OK)
                    return ret;
                at_col = want_col;
            }
            /* read 512 bytes or data_size, whichever is smaller*/
            read_size = data_size > 512 ? 512 : data_size;
            davinci_read_block_data(nand, data, read_size);
            data += read_size;
            data_size -= read_size;
            at_col += read_size;
        }
        want_col += 512;
 
        if (oob && oob_size) {
            if (want_col != at_col) {
                ret  = davinci_seek_column(nand, want_col);
                if (ret != ERROR_OK)
                    return ret;
                at_col = want_col;
            }
            /* read this "out-of-band" data -- infix */
            read_size = oob_size > 16 ? 16 : oob_size;
            davinci_read_block_data(nand, oob, read_size);
            oob += read_size;
            oob_size -= read_size;
            at_col += read_size;
        }
        want_col += 16;
    }
    return ERROR_OK;
}
 
NAND_DEVICE_COMMAND_HANDLER(davinci_nand_device_command)
{
    struct davinci_nand *info;
    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 (CMD_ARGC < 5)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    COMMAND_PARSE_NUMBER(ulong, CMD_ARGV[2], chip);
    if (chip == 0) {
        LOG_ERROR("Invalid NAND chip address %s", CMD_ARGV[2]);
        goto fail;
    }
 
    if (strcmp(CMD_ARGV[3], "hwecc1") == 0)
        eccmode = HWECC1;
    else if (strcmp(CMD_ARGV[3], "hwecc4") == 0)
        eccmode = HWECC4;
    else if (strcmp(CMD_ARGV[3], "hwecc4_infix") == 0)
        eccmode = HWECC4_INFIX;
    else {
        LOG_ERROR("Invalid ecc mode %s", CMD_ARGV[3]);
        goto fail;
    }
 
    COMMAND_PARSE_NUMBER(ulong, CMD_ARGV[4], aemif);
    if (aemif == 0) {
        LOG_ERROR("Invalid AEMIF controller address %s", CMD_ARGV[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)
        goto fail;
 
    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 = nand->target;
    info->io.data = info->data;
    info->io.op = ARM_NAND_NONE;
 
    /* 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;
}
 
struct nand_flash_controller davinci_nand_controller = {
    .name                   = "davinci",
    .usage                  = "chip_addr hwecc_mode aemif_addr",
    .nand_device_command    = davinci_nand_device_command,
    .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,
};