DOC support update

DOC support update

[Dan Brown]

The new NAND-subsystem-based DiskOnChip driver should now be fairly close to
providing proper JFFS2 support, if it doesn't already.  A tricky issue with
the hardware ECC generator was discovered today, and hopefully solved.

I say hopefully because I won't have a chance to really test it myself until
Monday.  However, interested folks who don't have vital data on their DOC
devices are welcome to do so and provide feedback.

Brief HOWTO (better HOWTO coming soon!):

- Have a DOC Millenium or DOC2000 TSOP.  Millenium+ is not supported (other
folks are hard at work on this).  DOC2000 original does not have BBT
handling yet (coming soon!) and should not be used with JFFS2 yet.

- Load the new diskonchip module (there is now a kernel configuration option
for this under NAND devices).  If your DOC device is not at window D000,
you'll have to edit the source or remap your chip.  Proper probing coming
soon!

- A bunch of mtd devices should be created.  mtd0 is the whole DOC.  The
others are partitions created by M-Systems.  A "BDK" partition is probably
the M-Sys BIOS driver.  A "BDTL" partition is where your INFTL filesystem
used to be.  I say used to be, because you're about to trash it.

- You can review the list of devices with 'cat /proc/mtd'

- Assuming your BDTL partition is mtd3:

    flash_eraseall -j /dev/mtd3
    mkfs.jffs2 -p -e 16384 -n -q -r <rootdir> -o <outputfile>
    nandwrite /dev/mtd3 <outputfile from above>
    mount -t jffs2 /dev/mtdblock3 <mountpoint>

- Cross your fingers.



Results, comments, etc appreciated.

    -Dan Brown

Re: DOC support update

[Thomas Gleixner]

On Saturday 19 June 2004 01:30, Dan Brown wrote:

> The new NAND-subsystem-based DiskOnChip driver should now be fairly close
> to providing proper JFFS2 support, if it doesn't already.  A tricky issue
> with the hardware ECC generator was discovered today, and hopefully solved.

Kudos to Dan for all his efforts.

> - Have a DOC Millenium or DOC2000 TSOP.  Millenium+ is not supported (other
> folks are hard at work on this).  DOC2000 original does not have BBT
> handling yet (coming soon!) and should not be used with JFFS2 yet.

Please join this effort as it will provide all the benefits of the generic 
mtd/nand subsystem and help us avoid to have redundant and incompatible code. 
At least the prospect to run JFFS2 or YAFFS on DoC should convince you of the 
worthiness of this effort.

I'm positive that the Millenium+ efforts will show up with similar results 
soon. The general problems of DoC support seem to be solved so it should be a 
straight forward task despite of the device specific oddities to get it 
running soon.

Please note that we plan to obsolete the DoC drivers in drivers/mtd/devices in 
the long run and switch the DoC support completely over to mtd/nand. This 
will affect the (I)NFTL layers too, as they will benefit from the nand  
functionality too. 

-- 
Thomas
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