[PATCH v2] mtd: gpmi: add NAND write verify support

[Huang Shijie]

sorry, I forgot to free the verify buffer.

send another patch as soon as possible.

On Sat, Aug 11, 2012 at 11:25 PM, Huang Shijie <shijie8 at gmail.com> wrote:
> Add NAND write verify support in gpmi-nand driver.
>
> This patch fixes a kernel crash when we select
> CONFIG_MTD_NAND_VERIFY_WRITE=y, and do some write tests:
>
> root at freescale /$ dd if=/dev/zero of=/dev/mtd0 bs=128k count=1
> [   41.070000] Unable to handle kernel NULL pointer dereference at virtual addr0
> [   41.080000] pgd = c77ac000
> [   41.080000] [00000000] *pgd=4773c831, *pte=00000000, *ppte=00000000
> [   41.090000] Internal error: Oops: 17 [#1] ARM
> [   41.090000] Modules linked in:
> [   41.090000] CPU: 0    Not tainted (3.6.0-rc1-next-20120809-00002-ga25d017-d)
> [   41.090000] PC is at nand_verify_buf+0x18/0x5c
> [   41.090000] LR is at nand_write_page+0xc0/0x140
> [   41.090000] pc : [<c023e7d4>]    lr : [<c023fcfc>]    psr: 20000013
> [   41.090000] sp : c7779de4  ip : 00000000  fp : c6e60000
> [   41.090000] r10: 00000000  r9 : 00020000  r8 : 00000000
> [   41.090000] r7 : 00000000  r6 : c6e60000  r5 : c762cb10  r4 : 00000000
> [   41.090000] r3 : c762c8a8  r2 : 00000800  r1 : c6e60000  r0 : 00000000
> [   41.090000] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
> [   41.090000] Control: 0005317f  Table: 477ac000  DAC: 00000015
> [   41.090000] Process dd (pid: 427, stack limit = 0xc7778270)
> [   41.090000] Stack: (0xc7779de4 to 0xc777a000)
>         ...
>
> Cc: <stable at vger.kernel.org>
> Signed-off-by: Huang Shijie <shijie8 at gmail.com>
> ---
> change log:
>     [1] use the mtd->writesize to allocate the verify buffer.
>     [2] add new field `verify_buf` in gpmi_nand_data{}
>
>     tested this patch on imx6q-arm2 board.
> ---
>  drivers/mtd/nand/gpmi-nand/gpmi-nand.c |   23 +++++++++++++++++++++++
>  drivers/mtd/nand/gpmi-nand/gpmi-nand.h |    1 +
>  2 files changed, 24 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> index 8c0d2f0..d98bdea 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> @@ -1512,12 +1512,34 @@ static int gpmi_pre_bbt_scan(struct gpmi_nand_data  *this)
>         return nand_boot_init(this);
>  }
>
> +static int gpmi_verify_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
> +{
> +       struct nand_chip *chip = mtd->priv;
> +       struct gpmi_nand_data *this = chip->priv;
> +       int ret;
> +
> +       ret = chip->ecc.read_page(mtd, chip, this->verify_buf, 0, 0);
> +       if (ret)
> +               return -EFAULT;
> +       if (memcmp(buf, this->verify_buf, len))
> +               return -EFAULT;
> +       return 0;
> +}
> +
>  static int gpmi_scan_bbt(struct mtd_info *mtd)
>  {
>         struct nand_chip *chip = mtd->priv;
>         struct gpmi_nand_data *this = chip->priv;
>         int ret;
>
> +       /*
> +        * We have gotten the right page size now, use it to allocate
> +        * the proper verify buffer.
> +        */
> +       this->verify_buf = kzalloc(mtd->writesize, GFP_KERNEL);
> +       if (!this->verify_buf)
> +               return -ENOMEM;
> +
>         /* Prepare for the BBT scan. */
>         ret = gpmi_pre_bbt_scan(this);
>         if (ret)
> @@ -1556,6 +1578,7 @@ static int __devinit gpmi_nfc_init(struct gpmi_nand_data *this)
>         chip->read_byte         = gpmi_read_byte;
>         chip->read_buf          = gpmi_read_buf;
>         chip->write_buf         = gpmi_write_buf;
> +       chip->verify_buf        = gpmi_verify_buf;
>         chip->ecc.read_page     = gpmi_ecc_read_page;
>         chip->ecc.write_page    = gpmi_ecc_write_page;
>         chip->ecc.read_oob      = gpmi_ecc_read_oob;
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
> index 1547a60..8ddf115 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.h
> @@ -144,6 +144,7 @@ struct gpmi_nand_data {
>         /* MTD / NAND */
>         struct nand_chip        nand;
>         struct mtd_info         mtd;
> +       uint8_t                 *verify_buf;
>
>         /* General-use Variables */
>         int                     current_chip;
> --
> 1.7.4.4
>