MTD and jffs2 mount problem on Linux-2.6.23 rc2

[Dach Miroslaw]

Hi Grant,

Thanks for your hints. As regards the endianness. I have tried both little and big endian options.
In my case only Big endian (native for ppc405) is accepted. There is however the CRC calculation mismatch
between the calculated one (by the kernel) during mounting the jffs2 and that one which is calculated by mkfs.jffs2.

I am however not sure that the Flash memory access in my case is fine for all modes A8 A16 A32.
I have got than idea to test jffs2 image stored somehow in RAM instead of Flash to test if jffs2 image generated by mkfs.jffs2 is consistent from kernel 2.6.23 point of view.

this what I have tried was:

losetup /dev/loop0 img2.jffs2  
mount -t jffs2 /dev/loop0 /mnt

unfortunately mount did not work.

Maybe it is possible somehow to use RAMDISK to emulate the Flash to mount jffs2 image?

Best Regards

M.


-----Original Message-----
From: Grant Erickson [mailto:gerickson at nuovations.com]
Sent: Tue 3/4/2008 8:40 PM
To: Dach Miroslaw
Subject: Re: MTD and jffs2 mount problem on Linux-2.6.23 rc2
 
On 3/4/08 11:29 AM, Dach Miroslaw wrote:
> In fact I have NOR flash. The 'dd' command to copy data to flash and backwards
> to the file works fine so I thing that 'dd' is not the issue.

Seems reasonable.

> I suspect that crc32 works differently when generating the jffs2 image file
> and the kernel uses different calculation methode? Maybe I am wrong.

Are you specifying an endianness/byte ordering on the command line when
creating the JFFS2 file system?

> Maybe it is the problem to access the Flash memory? Is there any method to
> mount jffs2 image in RAM instead of Flash just to test the jffs2 image
> consistency?

If your kernel is so configured, you should be able to mount it via the
loopback device:

    mount -t loop root.img /mnt

Regards,

Grant