NAND-Flash ECC data not used

NAND-Flash ECC data not used

[Juergen Beisert]

Hello all,

I have tried to use a 16MiB NAND flash in my application. It seems to work, 
but it also seem that the driver is not using the ECC data. I have derived my 
small driver from the spia.c source and have added the line

this->eccmode=NAND_ECC_SOFT;

before calling nand_scan(). nand_scan() inserts the ECC check routines 
correctly in the structure. But later, if the jffs2 calls the driver to read 
data from flash, it calls nand_read_ecc() with parameter oobsel = 0. So the 
line 

int	eccmode = oobsel ? this->eccmode : NAND_ECC_NONE;

in nand_read_ecc() switches back to NONE ecc mode while reading.

Any ideas what's going wrong?

Juergen Beisert

Re: NAND-Flash ECC data not used

[Thomas Gleixner]

On Tuesday 08 July 2003 10:01, Juergen Beisert wrote:
> Hello all,
>
> I have tried to use a 16MiB NAND flash in my application. It seems to work,
> but it also seem that the driver is not using the ECC data. I have derived
> my small driver from the spia.c source and have added the line
>
> this->eccmode=NAND_ECC_SOFT;
>
> before calling nand_scan(). nand_scan() inserts the ECC check routines
> correctly in the structure. But later, if the jffs2 calls the driver to
> read data from flash, it calls nand_read_ecc() with parameter oobsel = 0.
> So the line
>
> int	eccmode = oobsel ? this->eccmode : NAND_ECC_NONE;
>
> in nand_read_ecc() switches back to NONE ecc mode while reading.

Have you enabled CONFIG_JFFS2_NAND ?

This happens on boot up too, if you have not given the fs type in the 
commandline and the kernel tries to mount the partition with ext2 first.
It should not happen with jffs2.
-- 
Thomas
________________________________________________________________________
linutronix - competence in embedded & realtime linux
http://www.linutronix.de
mail: tglx@linutronix.de

Re: NAND-Flash ECC data not used

[Juergen Beisert]

Am Dienstag, 8. Juli 2003 12:42 schrieben Sie:
> On Tuesday 08 July 2003 10:01, Juergen Beisert wrote:
>
> Have you enabled CONFIG_JFFS2_NAND ?

I cannot find any source- or "Config.in" file that uses or defines this macro. 
Not in my 2.4.21pre4 nor in the mtd snapshot (from July 1. 2003).

> This happens on boot up too, if you have not given the fs type in the
> commandline and the kernel tries to mount the partition with ext2 first.
> It should not happen with jffs2.

Id did: mount -t jffs2 /dev/mtdblock5 /flash

JB

Re: NAND-Flash ECC data not used

[Thomas Gleixner]

On Tuesday 08 July 2003 14:05, Juergen Beisert wrote:
> Am Dienstag, 8. Juli 2003 12:42 schrieben Sie:
> > On Tuesday 08 July 2003 10:01, Juergen Beisert wrote:
> >
> > Have you enabled CONFIG_JFFS2_NAND ?
>
> I cannot find any source- or "Config.in" file that uses or defines this
> macro. Not in my 2.4.21pre4 nor in the mtd snapshot (from July 1. 2003).
>
> > This happens on boot up too, if you have not given the fs type in the
> > commandline and the kernel tries to mount the partition with ext2 first.
> > It should not happen with jffs2.
>
mtd/fs/Config.in contains
dep_tristate 'Journalling Flash File System (JFFS) support' CONFIG_JFFS_FS 
$CONFIG_MTD
if [ "$CONFIG_JFFS_FS" = "y" -o "$CONFIG_JFFS_FS" = "m" ] ; then
   int 'JFFS debugging verbosity (0 = quiet, 3 = noisy)' 
CONFIG_JFFS_FS_VERBOSE 0
   bool 'JFFS stats available in /proc filesystem' CONFIG_JFFS_PROC_FS
fi
dep_tristate 'Journalling Flash File System v2 (JFFS2) support' 
CONFIG_JFFS2_FS $CONFIG_MTD
if [ "$CONFIG_JFFS2_FS" = "y" -o "$CONFIG_JFFS2_FS" = "m" ] ; then
   int 'JFFS2 debugging verbosity (0 = quiet, 2 = noisy)' 
CONFIG_JFFS2_FS_DEBUG 0
   bool 'JFFS2 support for NAND chips' CONFIG_JFFS2_FS_NAND
fi

This is patched into the linux/fs/Config.in by the patchin.sh script, which 
can be found in mtd/patches. It's recommended to use this script.

-- 
Thomas
________________________________________________________________________
linutronix - competence in embedded & realtime linux
http://www.linutronix.de
mail: tglx@linutronix.de

Re: NAND-Flash ECC data not used

[Juergen Beisert]

Am Dienstag, 8. Juli 2003 18:11 schrieben Sie:
> On Tuesday 08 July 2003 14:05, Juergen Beisert wrote:
> > Am Dienstag, 8. Juli 2003 12:42 schrieben Sie:
> > > On Tuesday 08 July 2003 10:01, Juergen Beisert wrote:
> > >
> > > Have you enabled CONFIG_JFFS2_NAND ?
                                      ^^^^^^^^^^^^^^^^^^^^^^^
Sorry, I have searched for the macro CONFIG_JFFS2_NAND, not for 
CONFIG_JFFS2_FS_NAND.

Now I have find it and patched in. Seems to work now (with ECC).

Thanks a lot
JB