On Wednesday 12 August 2009 18:21:44 Murali N wrote:
> Hi All, i am seeing some weired issue with yaffs2 on my onenand driver.
>
> I have written basic onenand driver to test the read/write operations
> to the device.
> I am using 4Gb DDP device.Before enabling the DDP all read/writes are
> happening fine.
> After enabling the DDP feature i am able to read the files which falls
> on the chip boundary.
> but after  umount 7 mounting back the mtd partition i am loosing the
> files which falls on the chip boundary.
>
>
> Assumptions:
>
> 1) Using yaffs2 filesystem over mtd
> 2) Device 'KFN4G16Q2A DEB8
> 3) Read/write happends only one page at a time.Means MTD calls my
> driver reads/write functions when it want to read/program at page
> level.
> 4) Not using read-while-loading etc
>
>
> ex:
> suppose if i start writing a file X at the location 0x0fff_f800 (last
> page in chip0 ) to 0x1006_1800 ( in chip1 ).
> after umount & mount if try to read a file i am not able to retrieve
> back the file, it is showing as lost+found.
>
> while crossing the boundary i am taking care below settings
>
> 1) DFS/FBA based on 'from' address whether it is chip0 or chip1 address
> 2) DBS
> 3) FPA/FSA
> 4) BSA/BSC
>
> Is there anything else do i need to takecare?

I don't know much about DDP but it looks like there are/were issues with that.
eg. 
http://lists.infradead.org/pipermail/linux-mtd-cvs/2007-January/005696.html

This looks like an mtd issue best discussed on the mtd list.

-- Charles