[U-Boot-Users] M-Systems Disk on Chip and U-boot

[Wolfgang Denk]

In message <4137A05B.3070304 at udif.com> you wrote:
>
> If I understand correctly, the Linux MTD drivers has two layers. The 
> lower device level handles actual device access, while the upper layer 
> (NFTL, etc.) handles wear leveling.

In other words, one level is block device access, the  other  one  is
more or less filesystem related.

> 1. If I undersnatd correctly, u-boot only implemented the lower level, 
> right? no NFTL driver is currently in U-boot.

Right. The intention was to be able to load a Linux kernel image from
the "binary partition" of the DoC, but not more. See
http://www.denx.de/doc/CPU86/advanced-topics.html#DISK-ON-CHIP
for details.

[Yes, sorry, this information didn't make it into the new DULG yet. I
really wish the board manufacturers would pay a  bit  to  keep  their
documentation up to date.]

> 2. Is the Linux MTD NFTL driver compatible (in terms of disk format) 
> with the M-sys TrueFFS driver ? can I use the same device with both 
> software stacks without corrupting it?

Dunno.

> 3. Which layer handles ECC correction?

Dunno.

> 4. What good is the current u-boot support if it has no NFTL, and hence 
> no wear leveling? I assume I can't just map the FAT commands over it 
> without NFTL, as it won't be reable (if written over NFTL).

You can boot a Linux kernel from the bianry partition on the DoC.

> 5. I understand the DoC has 2 partitions (at least the 8M models) - a 
> binary partition and the normal partition. what is the difference 
> between them?

One is - umm - a binary partition without a  filesystem  on  it,  the
other one is a filesystem partition.

> I plan adaptin gthe NFTL layer from the linux-MTD project into u-boot, 
> and add support for the FAT commands.

Fine.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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