nand_ecc_micron: added support for 4 bits on-die ECC

The patch below enables support for the 4-bits on-die ECC (aka internal 
ECC).
Some notes:
- it is detected and activate from nand_scan_tail().
- when called from nand_scan_ident() it fails as at least "atmel_nand.c" 
overwrites some setup
- if an 4-bits on-die capable Micron nand flash is detected it will kick in
- UBI works like a charm and nicely moves the bit-flipped page/block
- when performing "dd if=/dev/mtdblock1 of=/dev/null" and encountering 
such a bad page, it fails with an I/O error (is this correct ?)
- raw reads likely do not work. When the on-die ECC is enabled it will 
automatically correct bitflips...
- Tested on MT29F1G08ABBDAHC and MT29F2G08ABBEAH4

Signed-off-by: Jelle Martijn Kok <jmkok@youcom.nl>
---
  drivers/mtd/nand/Kconfig            |    7 +
  drivers/mtd/nand/Makefile           |    1 +
  drivers/mtd/nand/nand_base.c        |    9 ++
  drivers/mtd/nand/nand_ecc_micron.c  |  238 
+++++++++++++++++++++++++++++++++++
  include/linux/mtd/nand_ecc_micron.h |    9 ++
  5 files changed, 264 insertions(+), 0 deletions(-)
  create mode 100644 drivers/mtd/nand/nand_ecc_micron.c
  create mode 100644 include/linux/mtd/nand_ecc_micron.h

Have you considered my patch:

  http://lists.infradead.org/pipermail/linux-mtd/2013-March/046358.html

maybe we should try to consolidate?  I can make an updated patch if
there is interest.

On Mon, May 6, 2013 at 1:43 PM, Jelle Martijn Kok <jmkok@youcom.nl> wrote:
> The patch below enables support for the 4-bits on-die ECC (aka internal
> ECC).
> Some notes:
> - it is detected and activate from nand_scan_tail().
> - when called from nand_scan_ident() it fails as at least "atmel_nand.c"
> overwrites some setup
> - if an 4-bits on-die capable Micron nand flash is detected it will kick in
> - UBI works like a charm and nicely moves the bit-flipped page/block
> - when performing "dd if=/dev/mtdblock1 of=/dev/null" and encountering such
> a bad page, it fails with an I/O error (is this correct ?)
> - raw reads likely do not work. When the on-die ECC is enabled it will
> automatically correct bitflips...
> - Tested on MT29F1G08ABBDAHC and MT29F2G08ABBEAH4
>
> Signed-off-by: Jelle Martijn Kok <jmkok@youcom.nl>
> ---
>  drivers/mtd/nand/Kconfig            |    7 +
>  drivers/mtd/nand/Makefile           |    1 +
>  drivers/mtd/nand/nand_base.c        |    9 ++
>  drivers/mtd/nand/nand_ecc_micron.c  |  238
> +++++++++++++++++++++++++++++++++++
>  include/linux/mtd/nand_ecc_micron.h |    9 ++
>  5 files changed, 264 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/mtd/nand/nand_ecc_micron.c
>  create mode 100644 include/linux/mtd/nand_ecc_micron.h
>
> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
> index cce7b70..54afcaa 100644
> --- a/drivers/mtd/nand/Kconfig
> +++ b/drivers/mtd/nand/Kconfig
> @@ -46,6 +46,13 @@ config MTD_NAND_ECC_BCH
>        ECC codes. They are used with NAND devices requiring more than 1 bit
>        of error correction.
>
> +config MTD_NAND_ECC_MICRON
> +    bool "Support Micron internal ECC"
> +    default n
> +    help
> +      This enables support for Micron 4-bits internal ECC
> +      Do not enable this if you will not be using it
> +
>  config MTD_SM_COMMON
>      tristate
>      default n
> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
> index 618f4ba..4db54de 100644
> --- a/drivers/mtd/nand/Makefile
> +++ b/drivers/mtd/nand/Makefile
> @@ -49,5 +49,6 @@ obj-$(CONFIG_MTD_NAND_MPC5121_NFC)    += mpc5121_nfc.o
>  obj-$(CONFIG_MTD_NAND_RICOH)        += r852.o
>  obj-$(CONFIG_MTD_NAND_JZ4740)        += jz4740_nand.o
>  obj-$(CONFIG_MTD_NAND_GPMI_NAND)    += gpmi-nand/
> +obj-$(CONFIG_MTD_NAND_ECC_MICRON)    += nand_ecc_micron.o
>
>  nand-objs := nand_base.o nand_bbt.o
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index daed698..70a2415 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -42,6 +42,7 @@
>  #include <linux/mtd/mtd.h>
>  #include <linux/mtd/nand.h>
>  #include <linux/mtd/nand_ecc.h>
> +#include <linux/mtd/nand_ecc_micron.h>
>  #include <linux/mtd/nand_bch.h>
>  #include <linux/interrupt.h>
>  #include <linux/bitops.h>
> @@ -3234,6 +3235,14 @@ int nand_scan_tail(struct mtd_info *mtd)
>      int i;
>      struct nand_chip *chip = mtd->priv;
>
> +#ifdef CONFIG_MTD_NAND_ECC_MICRON
> +    /* Detect and enable Micron 4-bits internal ECC */
> +    if (nand_ecc_micron_present(mtd)) {
> +        pr_info("NAND device: Using micron 4-bit internal ECC\n");
> +        nand_ecc_micron_init(mtd);
> +    }
> +#endif
> +
>      if (!(chip->options & NAND_OWN_BUFFERS))
>          chip->buffers = kmalloc(sizeof(*chip->buffers), GFP_KERNEL);
>      if (!chip->buffers)
> diff --git a/drivers/mtd/nand/nand_ecc_micron.c
> b/drivers/mtd/nand/nand_ecc_micron.c
> new file mode 100644
> index 0000000..49afaaf
> --- /dev/null
> +++ b/drivers/mtd/nand/nand_ecc_micron.c
> @@ -0,0 +1,238 @@
> +#include <linux/delay.h>
> +#include <linux/mtd/mtd.h>
> +#include <linux/mtd/nand.h>
> +#include <linux/mtd/nand_ecc_micron.h>
> +
> +/* Define the oob placement for the micron internal ECC nand */
> +static struct nand_ecclayout nand_oob_micron_ecc_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 },
> +    },
> +};
> +
> +/**
> + * nand_command_ecc_micron
> + * @mtd: MTD device structure
> + * @command: the command to be sent
> + * @column: the column address for this command, -1 if none
> + * @page_addr: the page address for this command, -1 if none
> + *
> + * Identical to nand_command_lp, but additionally checks the micron
> + * status after a NAND_CMD_READ0.
> + */
> +
> +static void nand_command_ecc_micron(struct mtd_info *mtd, unsigned int
> command,
> +                int column, int page_addr)
> +{
> +    register struct nand_chip *chip = mtd->priv;
> +
> +    /* Emulate NAND_CMD_READOOB */
> +    if (command == NAND_CMD_READOOB) {
> +        column += mtd->writesize;
> +        command = NAND_CMD_READ0;
> +    }
> +
> +    /* Command latch cycle */
> +    chip->cmd_ctrl(mtd, command & 0xff,
> +               NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
> +
> +    if (column != -1 || page_addr != -1) {
> +        int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
> +
> +        /* Serially input address */
> +        if (column != -1) {
> +            /* Adjust columns for 16 bit buswidth */
> +            if (chip->options & NAND_BUSWIDTH_16)
> +                column >>= 1;
> +            chip->cmd_ctrl(mtd, column, ctrl);
> +            ctrl &= ~NAND_CTRL_CHANGE;
> +            chip->cmd_ctrl(mtd, column >> 8, ctrl);
> +        }
> +        if (page_addr != -1) {
> +            chip->cmd_ctrl(mtd, page_addr, ctrl);
> +            chip->cmd_ctrl(mtd, page_addr >> 8,
> +                       NAND_NCE | NAND_ALE);
> +            /* One more address cycle for devices > 128MiB */
> +            if (chip->chipsize > (128 << 20))
> +                chip->cmd_ctrl(mtd, page_addr >> 16,
> +                           NAND_NCE | NAND_ALE);
> +        }
> +    }
> +    chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
> +
> +    /*
> +     * Program and erase have their own busy handlers status, sequential
> +     * in, and deplete1 need no delay.
> +     */
> +    switch (command) {
> +
> +    case NAND_CMD_CACHEDPROG:
> +    case NAND_CMD_PAGEPROG:
> +    case NAND_CMD_ERASE1:
> +    case NAND_CMD_ERASE2:
> +    case NAND_CMD_SEQIN:
> +    case NAND_CMD_RNDIN:
> +    case NAND_CMD_STATUS:
> +    case NAND_CMD_DEPLETE1:
> +        return;
> +
> +    case NAND_CMD_STATUS_ERROR:
> +    case NAND_CMD_STATUS_ERROR0:
> +    case NAND_CMD_STATUS_ERROR1:
> +    case NAND_CMD_STATUS_ERROR2:
> +    case NAND_CMD_STATUS_ERROR3:
> +        /* Read error status commands require only a short delay */
> +        udelay(chip->chip_delay);
> +        return;
> +
> +    case NAND_CMD_RESET:
> +        if (chip->dev_ready)
> +            break;
> +        udelay(chip->chip_delay);
> +        chip->cmd_ctrl(mtd, NAND_CMD_STATUS,
> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
> +                   NAND_NCE | NAND_CTRL_CHANGE);
> +        while (!(chip->read_byte(mtd) & NAND_STATUS_READY))
> +                ;
> +        return;
> +
> +    case NAND_CMD_RNDOUT:
> +        /* No ready / busy check necessary */
> +        chip->cmd_ctrl(mtd, NAND_CMD_RNDOUTSTART,
> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
> +                   NAND_NCE | NAND_CTRL_CHANGE);
> +        return;
> +
> +    case NAND_CMD_READ0:
> +        chip->cmd_ctrl(mtd, NAND_CMD_READSTART,
> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
> +                   NAND_NCE | NAND_CTRL_CHANGE);
> +
> +        /* This applies to read commands */
> +    default:
> +        /*
> +         * If we don't have access to the busy pin, we apply the given
> +         * command delay.
> +         */
> +        if (!chip->dev_ready) {
> +            udelay(chip->chip_delay);
> +            return;
> +        }
> +    }
> +
> +    /* Some additional things need to be done on read */
> +    if (command == NAND_CMD_READ0) {
> +        int status,cnt;
> +        /* Wait until nand flash is ready - tR_ECC max */
> +        for (cnt=0; cnt<70; cnt++) {
> +            ndelay(1000); /* 1 usec delay */
> +            chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
> +            status = chip->read_byte(mtd);
> +            if (status & NAND_STATUS_READY)
> +                break;
> +        }
> +        /* Check the status bits */
> +        if (status & NAND_STATUS_FAIL)
> +            mtd->ecc_stats.failed++;
> +        if (status & NAND_STATUS_REWRITE)
> +            mtd->ecc_stats.corrected++;
> +        /* Re-issue CMD0 after the status check */
> +        chip->cmd_ctrl(mtd, NAND_CMD_READ0,NAND_NCE | NAND_CLE |
> NAND_CTRL_CHANGE);
> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,NAND_NCE | NAND_CTRL_CHANGE);
> +    }
> +
> +    /*
> +     * Apply this short delay always to ensure that we do wait tWB in
> +     * any case on any machine.
> +     */
> +    ndelay(100);
> +
> +    nand_wait_ready(mtd);
> +}
> +
> +/**
> + * nand_read_page_ecc_micron - IDENTICAL to nand_read_page_raw
> + * @mtd: mtd info structure
> + * @chip: nand chip info structure
> + * @buf: buffer to store read data
> + * @page: page number to read
> + */
> +
> +static int nand_read_page_ecc_micron(struct mtd_info *mtd, struct nand_chip
> *chip, uint8_t *buf, int page) {
> +    chip->read_buf(mtd, buf, mtd->writesize);
> +    chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
> +    return 0;
> +}
> +
> +/**
> + * nand_write_page_ecc_micron - IDENTICAL to nand_write_page_raw
> + * @mtd: mtd info structure
> + * @chip: nand chip info structure
> + * @buf: data buffer
> + */
> +
> +static void nand_write_page_ecc_micron(struct mtd_info *mtd, struct
> nand_chip *chip, const uint8_t *buf) {
> +    chip->write_buf(mtd, buf, mtd->writesize);
> +    chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
> +}
> +
> +int nand_ecc_micron_present(struct mtd_info *mtd) {
> +    int i;
> +    u8 id_data[5];
> +    struct nand_chip *chip = mtd->priv;
> +
> +    /* Currently it seems it cannot be detected by onfi, but only via
> READID byte 4.
> +     * So see if byte 4 indicates internal ECC is present (we do not
> require it to
> +     * be already enabled. This might be the case if the kernel is loaded
> from another
> +     * source (NOR flash, SD card or network)
> +     * We ALWAYS enabled internal ECC if present, if you do not wish this,
> then do not
> +     * enable this feature in the kernel config
> +     */
> +    if (chip->onfi_params.jedec_id != NAND_MFR_MICRON)
> +        return 0;
> +    chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
> +    for (i = 0; i < 5; i++)
> +        id_data[i] = chip->read_byte(mtd);
> +    if (id_data[0] == NAND_MFR_MICRON && (id_data[4] & 0x03) == 0x02)
> +        return 1;
> +    return 0;
> +}
> +
> +static char micron_enable_ecc[] = {0x08,0,0,0};
> +
> +void nand_ecc_micron_init(struct mtd_info *mtd) {
> +    struct nand_chip *chip = mtd->priv;
> +
> +    /* Setup the read/write functions
> +     * NOTE: we are required to do so, or we are not allowed to set the
> ecc.mode to NAND_ECC_HW */
> +    chip->ecc.read_page = nand_read_page_ecc_micron;
> +    chip->ecc.write_page = nand_write_page_ecc_micron;
> +
> +    /* We need to modify NAND_CMD_READ0, so hook into the cmdfunc */
> +    chip->cmdfunc = nand_command_ecc_micron;
> +
> +    /* Make sure the internel ECC engine of the nand is active */
> +    chip->cmd_ctrl(mtd, 0xEF, NAND_CTRL_CHANGE | NAND_NCE | NAND_CLE); /*
> SET FEATURES */
> +    chip->cmd_ctrl(mtd, 0x90, NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE); /*
> Array operation mode */
> +    chip->write_buf(mtd, micron_enable_ecc, 4);
> +    ndelay(1000); /* tFEAT 1 usec delay */
> +
> +    /* Setup the ecc structure */
> +    chip->ecc.layout = &nand_oob_micron_ecc_64;
> +    chip->ecc.mode = NAND_ECC_HW;
> +    chip->ecc.size = 512;
> +    chip->ecc.bytes = 8;
> +}
> diff --git a/include/linux/mtd/nand_ecc_micron.h
> b/include/linux/mtd/nand_ecc_micron.h
> new file mode 100644
> index 0000000..c270ddc
> --- /dev/null
> +++ b/include/linux/mtd/nand_ecc_micron.h
> @@ -0,0 +1,9 @@
> +#ifndef __LINUX_MTD_NAND_ECC_MICRON_H
> +#define __LINUX_MTD_NAND_ECC_MICRON_H
> +
> +#define NAND_STATUS_REWRITE 0x08
> +
> +int nand_ecc_micron_present(struct mtd_info *mtd);
> +void nand_ecc_micron_init(struct mtd_info *mtd);
> +
> +#endif /* __LINUX_MTD_NAND_ECC_MICRON_H */
> --
> 1.7.0.4
>
>
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

Hi David,

I looked at your code and I expect it to contain too many sub-patches to 
be accepted.
- do not modify any code in "nand_base.c" as this likely will get the 
code rejected
- adding "NAND_ECC_HW_ON_DIE" is a indeed good choice for the ecc.mode.
- do not add any onfi patches, do this in a separate patch
- do not add set_column(), do this in a separate patch
- set_on_die_ecc() should have 1us delay. So a raw read/write might not 
be that straight forward.

Note: It will be a pleasure to make any changes to my code if one of the 
maintainers would require this before it can be accepted.

Jelle Martijn

On 06-05-13 21:54, David Mosberger-Tang wrote:
> Have you considered my patch:
>
>    http://lists.infradead.org/pipermail/linux-mtd/2013-March/046358.html
>
> maybe we should try to consolidate?  I can make an updated patch if
> there is interest.
>
> On Mon, May 6, 2013 at 1:43 PM, Jelle Martijn Kok <jmkok@youcom.nl> wrote:
>> The patch below enables support for the 4-bits on-die ECC (aka internal
>> ECC).
>> Some notes:
>> - it is detected and activate from nand_scan_tail().
>> - when called from nand_scan_ident() it fails as at least "atmel_nand.c"
>> overwrites some setup
>> - if an 4-bits on-die capable Micron nand flash is detected it will kick in
>> - UBI works like a charm and nicely moves the bit-flipped page/block
>> - when performing "dd if=/dev/mtdblock1 of=/dev/null" and encountering such
>> a bad page, it fails with an I/O error (is this correct ?)
>> - raw reads likely do not work. When the on-die ECC is enabled it will
>> automatically correct bitflips...
>> - Tested on MT29F1G08ABBDAHC and MT29F2G08ABBEAH4
>>
>> Signed-off-by: Jelle Martijn Kok <jmkok@youcom.nl>
>> ---
>>   drivers/mtd/nand/Kconfig            |    7 +
>>   drivers/mtd/nand/Makefile           |    1 +
>>   drivers/mtd/nand/nand_base.c        |    9 ++
>>   drivers/mtd/nand/nand_ecc_micron.c  |  238
>> +++++++++++++++++++++++++++++++++++
>>   include/linux/mtd/nand_ecc_micron.h |    9 ++
>>   5 files changed, 264 insertions(+), 0 deletions(-)
>>   create mode 100644 drivers/mtd/nand/nand_ecc_micron.c
>>   create mode 100644 include/linux/mtd/nand_ecc_micron.h
>>
>> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
>> index cce7b70..54afcaa 100644
>> --- a/drivers/mtd/nand/Kconfig
>> +++ b/drivers/mtd/nand/Kconfig
>> @@ -46,6 +46,13 @@ config MTD_NAND_ECC_BCH
>>         ECC codes. They are used with NAND devices requiring more than 1 bit
>>         of error correction.
>>
>> +config MTD_NAND_ECC_MICRON
>> +    bool "Support Micron internal ECC"
>> +    default n
>> +    help
>> +      This enables support for Micron 4-bits internal ECC
>> +      Do not enable this if you will not be using it
>> +
>>   config MTD_SM_COMMON
>>       tristate
>>       default n
>> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
>> index 618f4ba..4db54de 100644
>> --- a/drivers/mtd/nand/Makefile
>> +++ b/drivers/mtd/nand/Makefile
>> @@ -49,5 +49,6 @@ obj-$(CONFIG_MTD_NAND_MPC5121_NFC)    += mpc5121_nfc.o
>>   obj-$(CONFIG_MTD_NAND_RICOH)        += r852.o
>>   obj-$(CONFIG_MTD_NAND_JZ4740)        += jz4740_nand.o
>>   obj-$(CONFIG_MTD_NAND_GPMI_NAND)    += gpmi-nand/
>> +obj-$(CONFIG_MTD_NAND_ECC_MICRON)    += nand_ecc_micron.o
>>
>>   nand-objs := nand_base.o nand_bbt.o
>> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
>> index daed698..70a2415 100644
>> --- a/drivers/mtd/nand/nand_base.c
>> +++ b/drivers/mtd/nand/nand_base.c
>> @@ -42,6 +42,7 @@
>>   #include <linux/mtd/mtd.h>
>>   #include <linux/mtd/nand.h>
>>   #include <linux/mtd/nand_ecc.h>
>> +#include <linux/mtd/nand_ecc_micron.h>
>>   #include <linux/mtd/nand_bch.h>
>>   #include <linux/interrupt.h>
>>   #include <linux/bitops.h>
>> @@ -3234,6 +3235,14 @@ int nand_scan_tail(struct mtd_info *mtd)
>>       int i;
>>       struct nand_chip *chip = mtd->priv;
>>
>> +#ifdef CONFIG_MTD_NAND_ECC_MICRON
>> +    /* Detect and enable Micron 4-bits internal ECC */
>> +    if (nand_ecc_micron_present(mtd)) {
>> +        pr_info("NAND device: Using micron 4-bit internal ECC\n");
>> +        nand_ecc_micron_init(mtd);
>> +    }
>> +#endif
>> +
>>       if (!(chip->options & NAND_OWN_BUFFERS))
>>           chip->buffers = kmalloc(sizeof(*chip->buffers), GFP_KERNEL);
>>       if (!chip->buffers)
>> diff --git a/drivers/mtd/nand/nand_ecc_micron.c
>> b/drivers/mtd/nand/nand_ecc_micron.c
>> new file mode 100644
>> index 0000000..49afaaf
>> --- /dev/null
>> +++ b/drivers/mtd/nand/nand_ecc_micron.c
>> @@ -0,0 +1,238 @@
>> +#include <linux/delay.h>
>> +#include <linux/mtd/mtd.h>
>> +#include <linux/mtd/nand.h>
>> +#include <linux/mtd/nand_ecc_micron.h>
>> +
>> +/* Define the oob placement for the micron internal ECC nand */
>> +static struct nand_ecclayout nand_oob_micron_ecc_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 },
>> +    },
>> +};
>> +
>> +/**
>> + * nand_command_ecc_micron
>> + * @mtd: MTD device structure
>> + * @command: the command to be sent
>> + * @column: the column address for this command, -1 if none
>> + * @page_addr: the page address for this command, -1 if none
>> + *
>> + * Identical to nand_command_lp, but additionally checks the micron
>> + * status after a NAND_CMD_READ0.
>> + */
>> +
>> +static void nand_command_ecc_micron(struct mtd_info *mtd, unsigned int
>> command,
>> +                int column, int page_addr)
>> +{
>> +    register struct nand_chip *chip = mtd->priv;
>> +
>> +    /* Emulate NAND_CMD_READOOB */
>> +    if (command == NAND_CMD_READOOB) {
>> +        column += mtd->writesize;
>> +        command = NAND_CMD_READ0;
>> +    }
>> +
>> +    /* Command latch cycle */
>> +    chip->cmd_ctrl(mtd, command & 0xff,
>> +               NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
>> +
>> +    if (column != -1 || page_addr != -1) {
>> +        int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
>> +
>> +        /* Serially input address */
>> +        if (column != -1) {
>> +            /* Adjust columns for 16 bit buswidth */
>> +            if (chip->options & NAND_BUSWIDTH_16)
>> +                column >>= 1;
>> +            chip->cmd_ctrl(mtd, column, ctrl);
>> +            ctrl &= ~NAND_CTRL_CHANGE;
>> +            chip->cmd_ctrl(mtd, column >> 8, ctrl);
>> +        }
>> +        if (page_addr != -1) {
>> +            chip->cmd_ctrl(mtd, page_addr, ctrl);
>> +            chip->cmd_ctrl(mtd, page_addr >> 8,
>> +                       NAND_NCE | NAND_ALE);
>> +            /* One more address cycle for devices > 128MiB */
>> +            if (chip->chipsize > (128 << 20))
>> +                chip->cmd_ctrl(mtd, page_addr >> 16,
>> +                           NAND_NCE | NAND_ALE);
>> +        }
>> +    }
>> +    chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
>> +
>> +    /*
>> +     * Program and erase have their own busy handlers status, sequential
>> +     * in, and deplete1 need no delay.
>> +     */
>> +    switch (command) {
>> +
>> +    case NAND_CMD_CACHEDPROG:
>> +    case NAND_CMD_PAGEPROG:
>> +    case NAND_CMD_ERASE1:
>> +    case NAND_CMD_ERASE2:
>> +    case NAND_CMD_SEQIN:
>> +    case NAND_CMD_RNDIN:
>> +    case NAND_CMD_STATUS:
>> +    case NAND_CMD_DEPLETE1:
>> +        return;
>> +
>> +    case NAND_CMD_STATUS_ERROR:
>> +    case NAND_CMD_STATUS_ERROR0:
>> +    case NAND_CMD_STATUS_ERROR1:
>> +    case NAND_CMD_STATUS_ERROR2:
>> +    case NAND_CMD_STATUS_ERROR3:
>> +        /* Read error status commands require only a short delay */
>> +        udelay(chip->chip_delay);
>> +        return;
>> +
>> +    case NAND_CMD_RESET:
>> +        if (chip->dev_ready)
>> +            break;
>> +        udelay(chip->chip_delay);
>> +        chip->cmd_ctrl(mtd, NAND_CMD_STATUS,
>> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
>> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
>> +                   NAND_NCE | NAND_CTRL_CHANGE);
>> +        while (!(chip->read_byte(mtd) & NAND_STATUS_READY))
>> +                ;
>> +        return;
>> +
>> +    case NAND_CMD_RNDOUT:
>> +        /* No ready / busy check necessary */
>> +        chip->cmd_ctrl(mtd, NAND_CMD_RNDOUTSTART,
>> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
>> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
>> +                   NAND_NCE | NAND_CTRL_CHANGE);
>> +        return;
>> +
>> +    case NAND_CMD_READ0:
>> +        chip->cmd_ctrl(mtd, NAND_CMD_READSTART,
>> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
>> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
>> +                   NAND_NCE | NAND_CTRL_CHANGE);
>> +
>> +        /* This applies to read commands */
>> +    default:
>> +        /*
>> +         * If we don't have access to the busy pin, we apply the given
>> +         * command delay.
>> +         */
>> +        if (!chip->dev_ready) {
>> +            udelay(chip->chip_delay);
>> +            return;
>> +        }
>> +    }
>> +
>> +    /* Some additional things need to be done on read */
>> +    if (command == NAND_CMD_READ0) {
>> +        int status,cnt;
>> +        /* Wait until nand flash is ready - tR_ECC max */
>> +        for (cnt=0; cnt<70; cnt++) {
>> +            ndelay(1000); /* 1 usec delay */
>> +            chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
>> +            status = chip->read_byte(mtd);
>> +            if (status & NAND_STATUS_READY)
>> +                break;
>> +        }
>> +        /* Check the status bits */
>> +        if (status & NAND_STATUS_FAIL)
>> +            mtd->ecc_stats.failed++;
>> +        if (status & NAND_STATUS_REWRITE)
>> +            mtd->ecc_stats.corrected++;
>> +        /* Re-issue CMD0 after the status check */
>> +        chip->cmd_ctrl(mtd, NAND_CMD_READ0,NAND_NCE | NAND_CLE |
>> NAND_CTRL_CHANGE);
>> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,NAND_NCE | NAND_CTRL_CHANGE);
>> +    }
>> +
>> +    /*
>> +     * Apply this short delay always to ensure that we do wait tWB in
>> +     * any case on any machine.
>> +     */
>> +    ndelay(100);
>> +
>> +    nand_wait_ready(mtd);
>> +}
>> +
>> +/**
>> + * nand_read_page_ecc_micron - IDENTICAL to nand_read_page_raw
>> + * @mtd: mtd info structure
>> + * @chip: nand chip info structure
>> + * @buf: buffer to store read data
>> + * @page: page number to read
>> + */
>> +
>> +static int nand_read_page_ecc_micron(struct mtd_info *mtd, struct nand_chip
>> *chip, uint8_t *buf, int page) {
>> +    chip->read_buf(mtd, buf, mtd->writesize);
>> +    chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
>> +    return 0;
>> +}
>> +
>> +/**
>> + * nand_write_page_ecc_micron - IDENTICAL to nand_write_page_raw
>> + * @mtd: mtd info structure
>> + * @chip: nand chip info structure
>> + * @buf: data buffer
>> + */
>> +
>> +static void nand_write_page_ecc_micron(struct mtd_info *mtd, struct
>> nand_chip *chip, const uint8_t *buf) {
>> +    chip->write_buf(mtd, buf, mtd->writesize);
>> +    chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
>> +}
>> +
>> +int nand_ecc_micron_present(struct mtd_info *mtd) {
>> +    int i;
>> +    u8 id_data[5];
>> +    struct nand_chip *chip = mtd->priv;
>> +
>> +    /* Currently it seems it cannot be detected by onfi, but only via
>> READID byte 4.
>> +     * So see if byte 4 indicates internal ECC is present (we do not
>> require it to
>> +     * be already enabled. This might be the case if the kernel is loaded
>> from another
>> +     * source (NOR flash, SD card or network)
>> +     * We ALWAYS enabled internal ECC if present, if you do not wish this,
>> then do not
>> +     * enable this feature in the kernel config
>> +     */
>> +    if (chip->onfi_params.jedec_id != NAND_MFR_MICRON)
>> +        return 0;
>> +    chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
>> +    for (i = 0; i < 5; i++)
>> +        id_data[i] = chip->read_byte(mtd);
>> +    if (id_data[0] == NAND_MFR_MICRON && (id_data[4] & 0x03) == 0x02)
>> +        return 1;
>> +    return 0;
>> +}
>> +
>> +static char micron_enable_ecc[] = {0x08,0,0,0};
>> +
>> +void nand_ecc_micron_init(struct mtd_info *mtd) {
>> +    struct nand_chip *chip = mtd->priv;
>> +
>> +    /* Setup the read/write functions
>> +     * NOTE: we are required to do so, or we are not allowed to set the
>> ecc.mode to NAND_ECC_HW */
>> +    chip->ecc.read_page = nand_read_page_ecc_micron;
>> +    chip->ecc.write_page = nand_write_page_ecc_micron;
>> +
>> +    /* We need to modify NAND_CMD_READ0, so hook into the cmdfunc */
>> +    chip->cmdfunc = nand_command_ecc_micron;
>> +
>> +    /* Make sure the internel ECC engine of the nand is active */
>> +    chip->cmd_ctrl(mtd, 0xEF, NAND_CTRL_CHANGE | NAND_NCE | NAND_CLE); /*
>> SET FEATURES */
>> +    chip->cmd_ctrl(mtd, 0x90, NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE); /*
>> Array operation mode */
>> +    chip->write_buf(mtd, micron_enable_ecc, 4);
>> +    ndelay(1000); /* tFEAT 1 usec delay */
>> +
>> +    /* Setup the ecc structure */
>> +    chip->ecc.layout = &nand_oob_micron_ecc_64;
>> +    chip->ecc.mode = NAND_ECC_HW;
>> +    chip->ecc.size = 512;
>> +    chip->ecc.bytes = 8;
>> +}
>> diff --git a/include/linux/mtd/nand_ecc_micron.h
>> b/include/linux/mtd/nand_ecc_micron.h
>> new file mode 100644
>> index 0000000..c270ddc
>> --- /dev/null
>> +++ b/include/linux/mtd/nand_ecc_micron.h
>> @@ -0,0 +1,9 @@
>> +#ifndef __LINUX_MTD_NAND_ECC_MICRON_H
>> +#define __LINUX_MTD_NAND_ECC_MICRON_H
>> +
>> +#define NAND_STATUS_REWRITE 0x08
>> +
>> +int nand_ecc_micron_present(struct mtd_info *mtd);
>> +void nand_ecc_micron_init(struct mtd_info *mtd);
>> +
>> +#endif /* __LINUX_MTD_NAND_ECC_MICRON_H */
>> --
>> 1.7.0.4
>>
>>
>>
>> ______________________________________________________
>> Linux MTD discussion mailing list
>> http://lists.infradead.org/mailman/listinfo/linux-mtd/
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

Jelle,

The patch was meant to provide working code, not for direct
integration.  I am working on submitting the changes in nice, small,
incremental steps.

  --david

On Wed, May 8, 2013 at 3:50 AM, Jelle Martijn Kok <jmkok@youcom.nl> wrote:
> Hi David,
>
> I looked at your code and I expect it to contain too many sub-patches to be
> accepted.
> - do not modify any code in "nand_base.c" as this likely will get the code
> rejected
> - adding "NAND_ECC_HW_ON_DIE" is a indeed good choice for the ecc.mode.
> - do not add any onfi patches, do this in a separate patch
> - do not add set_column(), do this in a separate patch
> - set_on_die_ecc() should have 1us delay. So a raw read/write might not be
> that straight forward.
>
> Note: It will be a pleasure to make any changes to my code if one of the
> maintainers would require this before it can be accepted.
>
> Jelle Martijn
>
>
> On 06-05-13 21:54, David Mosberger-Tang wrote:
>>
>> Have you considered my patch:
>>
>>    http://lists.infradead.org/pipermail/linux-mtd/2013-March/046358.html
>>
>> maybe we should try to consolidate?  I can make an updated patch if
>> there is interest.
>>
>> On Mon, May 6, 2013 at 1:43 PM, Jelle Martijn Kok <jmkok@youcom.nl> wrote:
>>>
>>> The patch below enables support for the 4-bits on-die ECC (aka internal
>>> ECC).
>>> Some notes:
>>> - it is detected and activate from nand_scan_tail().
>>> - when called from nand_scan_ident() it fails as at least "atmel_nand.c"
>>> overwrites some setup
>>> - if an 4-bits on-die capable Micron nand flash is detected it will kick
>>> in
>>> - UBI works like a charm and nicely moves the bit-flipped page/block
>>> - when performing "dd if=/dev/mtdblock1 of=/dev/null" and encountering
>>> such
>>> a bad page, it fails with an I/O error (is this correct ?)
>>> - raw reads likely do not work. When the on-die ECC is enabled it will
>>> automatically correct bitflips...
>>> - Tested on MT29F1G08ABBDAHC and MT29F2G08ABBEAH4
>>>
>>> Signed-off-by: Jelle Martijn Kok <jmkok@youcom.nl>
>>> ---
>>>   drivers/mtd/nand/Kconfig            |    7 +
>>>   drivers/mtd/nand/Makefile           |    1 +
>>>   drivers/mtd/nand/nand_base.c        |    9 ++
>>>   drivers/mtd/nand/nand_ecc_micron.c  |  238
>>> +++++++++++++++++++++++++++++++++++
>>>   include/linux/mtd/nand_ecc_micron.h |    9 ++
>>>   5 files changed, 264 insertions(+), 0 deletions(-)
>>>   create mode 100644 drivers/mtd/nand/nand_ecc_micron.c
>>>   create mode 100644 include/linux/mtd/nand_ecc_micron.h
>>>
>>> diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
>>> index cce7b70..54afcaa 100644
>>> --- a/drivers/mtd/nand/Kconfig
>>> +++ b/drivers/mtd/nand/Kconfig
>>> @@ -46,6 +46,13 @@ config MTD_NAND_ECC_BCH
>>>         ECC codes. They are used with NAND devices requiring more than 1
>>> bit
>>>         of error correction.
>>>
>>> +config MTD_NAND_ECC_MICRON
>>> +    bool "Support Micron internal ECC"
>>> +    default n
>>> +    help
>>> +      This enables support for Micron 4-bits internal ECC
>>> +      Do not enable this if you will not be using it
>>> +
>>>   config MTD_SM_COMMON
>>>       tristate
>>>       default n
>>> diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
>>> index 618f4ba..4db54de 100644
>>> --- a/drivers/mtd/nand/Makefile
>>> +++ b/drivers/mtd/nand/Makefile
>>> @@ -49,5 +49,6 @@ obj-$(CONFIG_MTD_NAND_MPC5121_NFC)    += mpc5121_nfc.o
>>>   obj-$(CONFIG_MTD_NAND_RICOH)        += r852.o
>>>   obj-$(CONFIG_MTD_NAND_JZ4740)        += jz4740_nand.o
>>>   obj-$(CONFIG_MTD_NAND_GPMI_NAND)    += gpmi-nand/
>>> +obj-$(CONFIG_MTD_NAND_ECC_MICRON)    += nand_ecc_micron.o
>>>
>>>   nand-objs := nand_base.o nand_bbt.o
>>> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
>>> index daed698..70a2415 100644
>>> --- a/drivers/mtd/nand/nand_base.c
>>> +++ b/drivers/mtd/nand/nand_base.c
>>> @@ -42,6 +42,7 @@
>>>   #include <linux/mtd/mtd.h>
>>>   #include <linux/mtd/nand.h>
>>>   #include <linux/mtd/nand_ecc.h>
>>> +#include <linux/mtd/nand_ecc_micron.h>
>>>   #include <linux/mtd/nand_bch.h>
>>>   #include <linux/interrupt.h>
>>>   #include <linux/bitops.h>
>>> @@ -3234,6 +3235,14 @@ int nand_scan_tail(struct mtd_info *mtd)
>>>       int i;
>>>       struct nand_chip *chip = mtd->priv;
>>>
>>> +#ifdef CONFIG_MTD_NAND_ECC_MICRON
>>> +    /* Detect and enable Micron 4-bits internal ECC */
>>> +    if (nand_ecc_micron_present(mtd)) {
>>> +        pr_info("NAND device: Using micron 4-bit internal ECC\n");
>>> +        nand_ecc_micron_init(mtd);
>>> +    }
>>> +#endif
>>> +
>>>       if (!(chip->options & NAND_OWN_BUFFERS))
>>>           chip->buffers = kmalloc(sizeof(*chip->buffers), GFP_KERNEL);
>>>       if (!chip->buffers)
>>> diff --git a/drivers/mtd/nand/nand_ecc_micron.c
>>> b/drivers/mtd/nand/nand_ecc_micron.c
>>> new file mode 100644
>>> index 0000000..49afaaf
>>> --- /dev/null
>>> +++ b/drivers/mtd/nand/nand_ecc_micron.c
>>> @@ -0,0 +1,238 @@
>>> +#include <linux/delay.h>
>>> +#include <linux/mtd/mtd.h>
>>> +#include <linux/mtd/nand.h>
>>> +#include <linux/mtd/nand_ecc_micron.h>
>>> +
>>> +/* Define the oob placement for the micron internal ECC nand */
>>> +static struct nand_ecclayout nand_oob_micron_ecc_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 },
>>> +    },
>>> +};
>>> +
>>> +/**
>>> + * nand_command_ecc_micron
>>> + * @mtd: MTD device structure
>>> + * @command: the command to be sent
>>> + * @column: the column address for this command, -1 if none
>>> + * @page_addr: the page address for this command, -1 if none
>>> + *
>>> + * Identical to nand_command_lp, but additionally checks the micron
>>> + * status after a NAND_CMD_READ0.
>>> + */
>>> +
>>> +static void nand_command_ecc_micron(struct mtd_info *mtd, unsigned int
>>> command,
>>> +                int column, int page_addr)
>>> +{
>>> +    register struct nand_chip *chip = mtd->priv;
>>> +
>>> +    /* Emulate NAND_CMD_READOOB */
>>> +    if (command == NAND_CMD_READOOB) {
>>> +        column += mtd->writesize;
>>> +        command = NAND_CMD_READ0;
>>> +    }
>>> +
>>> +    /* Command latch cycle */
>>> +    chip->cmd_ctrl(mtd, command & 0xff,
>>> +               NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
>>> +
>>> +    if (column != -1 || page_addr != -1) {
>>> +        int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
>>> +
>>> +        /* Serially input address */
>>> +        if (column != -1) {
>>> +            /* Adjust columns for 16 bit buswidth */
>>> +            if (chip->options & NAND_BUSWIDTH_16)
>>> +                column >>= 1;
>>> +            chip->cmd_ctrl(mtd, column, ctrl);
>>> +            ctrl &= ~NAND_CTRL_CHANGE;
>>> +            chip->cmd_ctrl(mtd, column >> 8, ctrl);
>>> +        }
>>> +        if (page_addr != -1) {
>>> +            chip->cmd_ctrl(mtd, page_addr, ctrl);
>>> +            chip->cmd_ctrl(mtd, page_addr >> 8,
>>> +                       NAND_NCE | NAND_ALE);
>>> +            /* One more address cycle for devices > 128MiB */
>>> +            if (chip->chipsize > (128 << 20))
>>> +                chip->cmd_ctrl(mtd, page_addr >> 16,
>>> +                           NAND_NCE | NAND_ALE);
>>> +        }
>>> +    }
>>> +    chip->cmd_ctrl(mtd, NAND_CMD_NONE, NAND_NCE | NAND_CTRL_CHANGE);
>>> +
>>> +    /*
>>> +     * Program and erase have their own busy handlers status, sequential
>>> +     * in, and deplete1 need no delay.
>>> +     */
>>> +    switch (command) {
>>> +
>>> +    case NAND_CMD_CACHEDPROG:
>>> +    case NAND_CMD_PAGEPROG:
>>> +    case NAND_CMD_ERASE1:
>>> +    case NAND_CMD_ERASE2:
>>> +    case NAND_CMD_SEQIN:
>>> +    case NAND_CMD_RNDIN:
>>> +    case NAND_CMD_STATUS:
>>> +    case NAND_CMD_DEPLETE1:
>>> +        return;
>>> +
>>> +    case NAND_CMD_STATUS_ERROR:
>>> +    case NAND_CMD_STATUS_ERROR0:
>>> +    case NAND_CMD_STATUS_ERROR1:
>>> +    case NAND_CMD_STATUS_ERROR2:
>>> +    case NAND_CMD_STATUS_ERROR3:
>>> +        /* Read error status commands require only a short delay */
>>> +        udelay(chip->chip_delay);
>>> +        return;
>>> +
>>> +    case NAND_CMD_RESET:
>>> +        if (chip->dev_ready)
>>> +            break;
>>> +        udelay(chip->chip_delay);
>>> +        chip->cmd_ctrl(mtd, NAND_CMD_STATUS,
>>> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
>>> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
>>> +                   NAND_NCE | NAND_CTRL_CHANGE);
>>> +        while (!(chip->read_byte(mtd) & NAND_STATUS_READY))
>>> +                ;
>>> +        return;
>>> +
>>> +    case NAND_CMD_RNDOUT:
>>> +        /* No ready / busy check necessary */
>>> +        chip->cmd_ctrl(mtd, NAND_CMD_RNDOUTSTART,
>>> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
>>> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
>>> +                   NAND_NCE | NAND_CTRL_CHANGE);
>>> +        return;
>>> +
>>> +    case NAND_CMD_READ0:
>>> +        chip->cmd_ctrl(mtd, NAND_CMD_READSTART,
>>> +                   NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
>>> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,
>>> +                   NAND_NCE | NAND_CTRL_CHANGE);
>>> +
>>> +        /* This applies to read commands */
>>> +    default:
>>> +        /*
>>> +         * If we don't have access to the busy pin, we apply the given
>>> +         * command delay.
>>> +         */
>>> +        if (!chip->dev_ready) {
>>> +            udelay(chip->chip_delay);
>>> +            return;
>>> +        }
>>> +    }
>>> +
>>> +    /* Some additional things need to be done on read */
>>> +    if (command == NAND_CMD_READ0) {
>>> +        int status,cnt;
>>> +        /* Wait until nand flash is ready - tR_ECC max */
>>> +        for (cnt=0; cnt<70; cnt++) {
>>> +            ndelay(1000); /* 1 usec delay */
>>> +            chip->cmdfunc(mtd, NAND_CMD_STATUS, -1, -1);
>>> +            status = chip->read_byte(mtd);
>>> +            if (status & NAND_STATUS_READY)
>>> +                break;
>>> +        }
>>> +        /* Check the status bits */
>>> +        if (status & NAND_STATUS_FAIL)
>>> +            mtd->ecc_stats.failed++;
>>> +        if (status & NAND_STATUS_REWRITE)
>>> +            mtd->ecc_stats.corrected++;
>>> +        /* Re-issue CMD0 after the status check */
>>> +        chip->cmd_ctrl(mtd, NAND_CMD_READ0,NAND_NCE | NAND_CLE |
>>> NAND_CTRL_CHANGE);
>>> +        chip->cmd_ctrl(mtd, NAND_CMD_NONE,NAND_NCE | NAND_CTRL_CHANGE);
>>> +    }
>>> +
>>> +    /*
>>> +     * Apply this short delay always to ensure that we do wait tWB in
>>> +     * any case on any machine.
>>> +     */
>>> +    ndelay(100);
>>> +
>>> +    nand_wait_ready(mtd);
>>> +}
>>> +
>>> +/**
>>> + * nand_read_page_ecc_micron - IDENTICAL to nand_read_page_raw
>>> + * @mtd: mtd info structure
>>> + * @chip: nand chip info structure
>>> + * @buf: buffer to store read data
>>> + * @page: page number to read
>>> + */
>>> +
>>> +static int nand_read_page_ecc_micron(struct mtd_info *mtd, struct
>>> nand_chip
>>> *chip, uint8_t *buf, int page) {
>>> +    chip->read_buf(mtd, buf, mtd->writesize);
>>> +    chip->read_buf(mtd, chip->oob_poi, mtd->oobsize);
>>> +    return 0;
>>> +}
>>> +
>>> +/**
>>> + * nand_write_page_ecc_micron - IDENTICAL to nand_write_page_raw
>>> + * @mtd: mtd info structure
>>> + * @chip: nand chip info structure
>>> + * @buf: data buffer
>>> + */
>>> +
>>> +static void nand_write_page_ecc_micron(struct mtd_info *mtd, struct
>>> nand_chip *chip, const uint8_t *buf) {
>>> +    chip->write_buf(mtd, buf, mtd->writesize);
>>> +    chip->write_buf(mtd, chip->oob_poi, mtd->oobsize);
>>> +}
>>> +
>>> +int nand_ecc_micron_present(struct mtd_info *mtd) {
>>> +    int i;
>>> +    u8 id_data[5];
>>> +    struct nand_chip *chip = mtd->priv;
>>> +
>>> +    /* Currently it seems it cannot be detected by onfi, but only via
>>> READID byte 4.
>>> +     * So see if byte 4 indicates internal ECC is present (we do not
>>> require it to
>>> +     * be already enabled. This might be the case if the kernel is
>>> loaded
>>> from another
>>> +     * source (NOR flash, SD card or network)
>>> +     * We ALWAYS enabled internal ECC if present, if you do not wish
>>> this,
>>> then do not
>>> +     * enable this feature in the kernel config
>>> +     */
>>> +    if (chip->onfi_params.jedec_id != NAND_MFR_MICRON)
>>> +        return 0;
>>> +    chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
>>> +    for (i = 0; i < 5; i++)
>>> +        id_data[i] = chip->read_byte(mtd);
>>> +    if (id_data[0] == NAND_MFR_MICRON && (id_data[4] & 0x03) == 0x02)
>>> +        return 1;
>>> +    return 0;
>>> +}
>>> +
>>> +static char micron_enable_ecc[] = {0x08,0,0,0};
>>> +
>>> +void nand_ecc_micron_init(struct mtd_info *mtd) {
>>> +    struct nand_chip *chip = mtd->priv;
>>> +
>>> +    /* Setup the read/write functions
>>> +     * NOTE: we are required to do so, or we are not allowed to set the
>>> ecc.mode to NAND_ECC_HW */
>>> +    chip->ecc.read_page = nand_read_page_ecc_micron;
>>> +    chip->ecc.write_page = nand_write_page_ecc_micron;
>>> +
>>> +    /* We need to modify NAND_CMD_READ0, so hook into the cmdfunc */
>>> +    chip->cmdfunc = nand_command_ecc_micron;
>>> +
>>> +    /* Make sure the internel ECC engine of the nand is active */
>>> +    chip->cmd_ctrl(mtd, 0xEF, NAND_CTRL_CHANGE | NAND_NCE | NAND_CLE);
>>> /*
>>> SET FEATURES */
>>> +    chip->cmd_ctrl(mtd, 0x90, NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE);
>>> /*
>>> Array operation mode */
>>> +    chip->write_buf(mtd, micron_enable_ecc, 4);
>>> +    ndelay(1000); /* tFEAT 1 usec delay */
>>> +
>>> +    /* Setup the ecc structure */
>>> +    chip->ecc.layout = &nand_oob_micron_ecc_64;
>>> +    chip->ecc.mode = NAND_ECC_HW;
>>> +    chip->ecc.size = 512;
>>> +    chip->ecc.bytes = 8;
>>> +}
>>> diff --git a/include/linux/mtd/nand_ecc_micron.h
>>> b/include/linux/mtd/nand_ecc_micron.h
>>> new file mode 100644
>>> index 0000000..c270ddc
>>> --- /dev/null
>>> +++ b/include/linux/mtd/nand_ecc_micron.h
>>> @@ -0,0 +1,9 @@
>>> +#ifndef __LINUX_MTD_NAND_ECC_MICRON_H
>>> +#define __LINUX_MTD_NAND_ECC_MICRON_H
>>> +
>>> +#define NAND_STATUS_REWRITE 0x08
>>> +
>>> +int nand_ecc_micron_present(struct mtd_info *mtd);
>>> +void nand_ecc_micron_init(struct mtd_info *mtd);
>>> +
>>> +#endif /* __LINUX_MTD_NAND_ECC_MICRON_H */
>>> --
>>> 1.7.0.4
>>>
>>>
>>>
>>> ______________________________________________________
>>> Linux MTD discussion mailing list
>>> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>>
>> ______________________________________________________
>> Linux MTD discussion mailing list
>> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>
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