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

Re: [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@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@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@vger.kernel.org>
> Signed-off-by: Huang Shijie <shijie8@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
>

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

[Huang Shijie]

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@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@vger.kernel.org>
Signed-off-by: Huang Shijie <shijie8@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

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

[Artem Bityutskiy]

On Sat, Aug 11, 2012 at 6:25 PM, Huang Shijie <shijie8@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:

I would just kill ONFIG_MTD_NAND_VERIFY_WRITE entirely. Some drivers
do not support it and it does not work for sub-pages for long time.
Both UBI and JFFS2 are able to read verify what they wrote already.
There are also MTD tests which do this verification. So I think there
is no reason to keep this in the NAND layer, let alone wasting RAM in
the driver to support this feature.

I am also removing the -stable mailing list - ne need to spam it.

-- 
Best Regards,
Artem Bityutskiy (Битюцкий Артём)

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

[Huang Shijie]

于 2012年08月13日 12:44, Artem Bityutskiy 写道:
> On Sat, Aug 11, 2012 at 6:25 PM, Huang Shijie<shijie8@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:
> I would just kill ONFIG_MTD_NAND_VERIFY_WRITE entirely. Some drivers
> do not support it and it does not work for sub-pages for long time.
> Both UBI and JFFS2 are able to read verify what they wrote already.
> There are also MTD tests which do this verification. So I think there
> is no reason to keep this in the NAND layer, let alone wasting RAM in
> the driver to support this feature.
>
> I am also removing the -stable mailing list - ne need to spam it.
>
thanks a lot. Maybe we should send a patch to remove the 
CONFIG_MTD_NAND_VERIFY_WRITE feature entirely.

Huang Shijie

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

[Artem Bityutskiy]

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On Mon, 2012-08-13 at 13:09 +0800, Huang Shijie wrote:
> 于 2012年08月13日 12:44, Artem Bityutskiy 写道:
> > On Sat, Aug 11, 2012 at 6:25 PM, Huang Shijie<shijie8@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:
> > I would just kill ONFIG_MTD_NAND_VERIFY_WRITE entirely. Some drivers
> > do not support it and it does not work for sub-pages for long time.
> > Both UBI and JFFS2 are able to read verify what they wrote already.
> > There are also MTD tests which do this verification. So I think there
> > is no reason to keep this in the NAND layer, let alone wasting RAM in
> > the driver to support this feature.
> >
> > I am also removing the -stable mailing list - ne need to spam it.
> >
> thanks a lot. Maybe we should send a patch to remove the 
> CONFIG_MTD_NAND_VERIFY_WRITE feature entirely.

I'd suggest that instead. I have huge back-log, so wouldn't be able to
process it quickly, but at some point I would take it to the l2 tree.

-- 
Best Regards,
Artem Bityutskiy

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