[Yaffs-archive] RE: 256 MBytes of NAND

[Christian Gan]

Hello Liam,

I've successfully modified mtdconcat(*) to be useful for NAND devices.
Currently I haven't submitted the code to the MTD folks because my testing
on it is too minimal.  Right now I have two 128MB parts (Toshiba)
concatenated.

The changes are straight forward, e.g. adding support for OOBs etc.  And I'd
be glad to share until I am confident enough to submit it.

(*) mtdconcat is a set of libraries that allow you to create one mtd device
out of N mtd devices.  In it's current state in the official MTD release it
is unusable for NAND flashes.

Christian

> -----Original Message-----
> From: Charles Manning [mailto:Charles.Manning@trimble.co.nz]
> Sent: Wednesday, January 15, 2003 3:35 PM
> To: 'Liam Breck'; yaffs@toby-churchill.org
> Subject: RE: 256 MBytes of NAND
>
>
> You can achieve 128 or 256 with a single chip these days. Samsung makes
> them, as do others. You can also get stacked parts to double the
> capacity of
> a single footprint.
>
> Some Samsung (and maybe other vendors') parts support a boot mode
> where you
> can do a linear read off the first block. This allows you to put your
> bootstrap into the NAND with some restrictions to the type of
> code you want
> to execute.
>
> I don't know if the MTD can aggregate NAND parts into a single partition,
> but this can definitely be done inside YAFFS if required. Achieving this
> inside the MTD is probably more desirable to facilitate mounting (ie.
> otherwise you'd have to have YAFFS mount two devices).
>
> NB That the devices to support the features you want might not be
> available
> in 512-byte page sizes. YAFFS2 (in the pipe) will support different page
> sizes so this should not be an issue by the time you have a board.
>
> -- Charles
>
>
>
>
> -----Original Message-----
> From: Liam Breck [mailto:liam@pointservers.org]
> Sent: Wednesday, 15 January 2003 7:01 p.m.
> To: yaffs@toby-churchill.org
> Subject: 256 MBytes of NAND
>
>
> We need 128-256 MBytes of NAND flash for a custom SBC.
> We need to boot from this flash.
>
> Are any chips available at that size, or do we have to use 2-4 chips?
>
> If multiple chips, can YAFFS or MTD aggregate them into a single
> partition?
>
> What vendors would folks recommend?
>
> Thanks,
>
>
> Liam Breck, Director
> PointServers.org                                  liam@pointservers.org
> Boston, Massachusetts                           http://pointservers.org/
>
>
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