diff mbox

mtd: nand: mxc: Fix mxc_v1 ooblayout

Message ID 1480065209-4179-1-git-send-email-boris.brezillon@free-electrons.com (mailing list archive)
State New, archived
Headers show

Commit Message

Boris BREZILLON Nov. 25, 2016, 9:13 a.m. UTC
Commit a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops")
introduced a bug in the OOB layout description. Even if the driver claims
that 3 ECC bytes are reserved to protect 512 bytes of data, it's actually
5 ECC bytes to protect 512+6 bytes of data (some OOB bytes are also
protected using extra ECC bytes).

Fix the mxc_v1_ooblayout_{free,ecc}() functions to reflect this behavior.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops")
Cc: <stable@vger.kernel.org>
---
 drivers/mtd/nand/mxc_nand.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Marek Vasut Nov. 25, 2016, 9:58 a.m. UTC | #1
On 11/25/2016 10:13 AM, Boris Brezillon wrote:
> Commit a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops")
> introduced a bug in the OOB layout description. Even if the driver claims
> that 3 ECC bytes are reserved to protect 512 bytes of data, it's actually
> 5 ECC bytes to protect 512+6 bytes of data (some OOB bytes are also
> protected using extra ECC bytes).
> 
> Fix the mxc_v1_ooblayout_{free,ecc}() functions to reflect this behavior.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> Fixes: a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops")
> Cc: <stable@vger.kernel.org>
> ---
>  drivers/mtd/nand/mxc_nand.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
> index 61ca020c5272..c19ec4f0983e 100644
> --- a/drivers/mtd/nand/mxc_nand.c
> +++ b/drivers/mtd/nand/mxc_nand.c
> @@ -886,7 +886,7 @@ static int mxc_v1_ooblayout_ecc(struct mtd_info *mtd, int section,
>  		return -ERANGE;
>  
>  	oobregion->offset = (section * 16) + 6;
> -	oobregion->length = nand_chip->ecc.bytes;
> +	oobregion->length = 5;

Use a macro instead of hard-coding a value please :)

>  	return 0;
>  }
> @@ -908,8 +908,7 @@ static int mxc_v1_ooblayout_free(struct mtd_info *mtd, int section,
>  			oobregion->length = 4;
>  		}
>  	} else {
> -		oobregion->offset = ((section - 1) * 16) +
> -				    nand_chip->ecc.bytes + 6;
> +		oobregion->offset = ((section - 1) * 16) + 5 + 6;

DTTO here, the math here is cryptic enough.

>  		if (section < nand_chip->ecc.steps)
>  			oobregion->length = (section * 16) + 6 -
>  					    oobregion->offset;
>
Boris BREZILLON Nov. 25, 2016, 10:27 a.m. UTC | #2
On Fri, 25 Nov 2016 10:58:26 +0100
Marek Vasut <marek.vasut@gmail.com> wrote:

> On 11/25/2016 10:13 AM, Boris Brezillon wrote:
> > Commit a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops")
> > introduced a bug in the OOB layout description. Even if the driver claims
> > that 3 ECC bytes are reserved to protect 512 bytes of data, it's actually
> > 5 ECC bytes to protect 512+6 bytes of data (some OOB bytes are also
> > protected using extra ECC bytes).
> > 
> > Fix the mxc_v1_ooblayout_{free,ecc}() functions to reflect this behavior.
> > 
> > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> > Fixes: a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops")
> > Cc: <stable@vger.kernel.org>
> > ---
> >  drivers/mtd/nand/mxc_nand.c | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
> > index 61ca020c5272..c19ec4f0983e 100644
> > --- a/drivers/mtd/nand/mxc_nand.c
> > +++ b/drivers/mtd/nand/mxc_nand.c
> > @@ -886,7 +886,7 @@ static int mxc_v1_ooblayout_ecc(struct mtd_info *mtd, int section,
> >  		return -ERANGE;
> >  
> >  	oobregion->offset = (section * 16) + 6;
> > -	oobregion->length = nand_chip->ecc.bytes;
> > +	oobregion->length = 5;  
> 
> Use a macro instead of hard-coding a value please :)

Ideally, we should change ->eccbytes value in the
imx27_nand_devtype_data and imx21_nand_devtype_data definitions, but I
fear it could break other things.

I'll define a macro.

> 
> >  	return 0;
> >  }
> > @@ -908,8 +908,7 @@ static int mxc_v1_ooblayout_free(struct mtd_info *mtd, int section,
> >  			oobregion->length = 4;
> >  		}
> >  	} else {
> > -		oobregion->offset = ((section - 1) * 16) +
> > -				    nand_chip->ecc.bytes + 6;
> > +		oobregion->offset = ((section - 1) * 16) + 5 + 6;  
> 
> DTTO here, the math here is cryptic enough.
> 
> >  		if (section < nand_chip->ecc.steps)
> >  			oobregion->length = (section * 16) + 6 -
> >  					    oobregion->offset;
> >   
> 
>
Marek Vasut Nov. 25, 2016, 10:40 a.m. UTC | #3
On 11/25/2016 11:27 AM, Boris Brezillon wrote:
> On Fri, 25 Nov 2016 10:58:26 +0100
> Marek Vasut <marek.vasut@gmail.com> wrote:
> 
>> On 11/25/2016 10:13 AM, Boris Brezillon wrote:
>>> Commit a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops")
>>> introduced a bug in the OOB layout description. Even if the driver claims
>>> that 3 ECC bytes are reserved to protect 512 bytes of data, it's actually
>>> 5 ECC bytes to protect 512+6 bytes of data (some OOB bytes are also
>>> protected using extra ECC bytes).
>>>
>>> Fix the mxc_v1_ooblayout_{free,ecc}() functions to reflect this behavior.
>>>
>>> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
>>> Fixes: a894cf6c5a82 ("mtd: nand: mxc: switch to mtd_ooblayout_ops")
>>> Cc: <stable@vger.kernel.org>
>>> ---
>>>  drivers/mtd/nand/mxc_nand.c | 5 ++---
>>>  1 file changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
>>> index 61ca020c5272..c19ec4f0983e 100644
>>> --- a/drivers/mtd/nand/mxc_nand.c
>>> +++ b/drivers/mtd/nand/mxc_nand.c
>>> @@ -886,7 +886,7 @@ static int mxc_v1_ooblayout_ecc(struct mtd_info *mtd, int section,
>>>  		return -ERANGE;
>>>  
>>>  	oobregion->offset = (section * 16) + 6;
>>> -	oobregion->length = nand_chip->ecc.bytes;
>>> +	oobregion->length = 5;  
>>
>> Use a macro instead of hard-coding a value please :)
> 
> Ideally, we should change ->eccbytes value in the
> imx27_nand_devtype_data and imx21_nand_devtype_data definitions, but I
> fear it could break other things.

I was wondering about that too :) Break what things ?

> I'll define a macro.

Thanks!

>>
>>>  	return 0;
>>>  }
>>> @@ -908,8 +908,7 @@ static int mxc_v1_ooblayout_free(struct mtd_info *mtd, int section,
>>>  			oobregion->length = 4;
>>>  		}
>>>  	} else {
>>> -		oobregion->offset = ((section - 1) * 16) +
>>> -				    nand_chip->ecc.bytes + 6;
>>> +		oobregion->offset = ((section - 1) * 16) + 5 + 6;  
>>
>> DTTO here, the math here is cryptic enough.
>>
>>>  		if (section < nand_chip->ecc.steps)
>>>  			oobregion->length = (section * 16) + 6 -
>>>  					    oobregion->offset;
>>>   
>>
>>
>
diff mbox

Patch

diff --git a/drivers/mtd/nand/mxc_nand.c b/drivers/mtd/nand/mxc_nand.c
index 61ca020c5272..c19ec4f0983e 100644
--- a/drivers/mtd/nand/mxc_nand.c
+++ b/drivers/mtd/nand/mxc_nand.c
@@ -886,7 +886,7 @@  static int mxc_v1_ooblayout_ecc(struct mtd_info *mtd, int section,
 		return -ERANGE;
 
 	oobregion->offset = (section * 16) + 6;
-	oobregion->length = nand_chip->ecc.bytes;
+	oobregion->length = 5;
 
 	return 0;
 }
@@ -908,8 +908,7 @@  static int mxc_v1_ooblayout_free(struct mtd_info *mtd, int section,
 			oobregion->length = 4;
 		}
 	} else {
-		oobregion->offset = ((section - 1) * 16) +
-				    nand_chip->ecc.bytes + 6;
+		oobregion->offset = ((section - 1) * 16) + 5 + 6;
 		if (section < nand_chip->ecc.steps)
 			oobregion->length = (section * 16) + 6 -
 					    oobregion->offset;