Does mtd support two-plane page program for nand flash?

[Marteo Tim]

MLC NAND Flash has already become the mainstream flash for
large-capacity on the market. But due to its low writting speed, there
will be introduced more parallel writting features such as multi-bank,
interleave, etc. So I think it is very necessary to modify MTD
structure to support multi-plane & interleave feature for speed
issure.

It is a good method to shield the details of flash type by composing
two or more page as a large page. Although it will be more slower for
small segment data read/write. But for large-capacity flash,
continuate writting speed maybe is more concerned.

Regards,
marteo

2007/3/9, Jörn Engel <joern at lazybastard.org>:
> On Fri, 9 March 2007 10:09:37 +0200, Adrian Hunter wrote:
> >
> > OneNAND DDP does this too (google: onenand "2x program")
>
> Thanks!
>
> > I presume the possibility exists to have the driver pretend that the
> > page size is twice as large and there are half as many erase blocks.
> > It would have to map the addressses accordingly - and everything
> > else would have to be willing to accept a 4KiB page with 8
> > subpages and 128 bytes of oob.
>
> That would be the quick way to get extra bandwidth.
>
> Interleaving writes to both planes can also help latency.  It is
> possible to write to one plane while the other is erasing.  It is
> possible to do two writes in parallel.  Keeping things seperate would
> keep writesize and erasesize low.  And by combining two or more planes,
> the slowest of them always decides how long a write/erase will take.
>
> So in the long run, I would prefer to keep planes seperate and add
> intelligence to filesystems, LogFS in particular.
>
> Jörn
>
> --
> It does not matter how slowly you go, so long as you do not stop.
> -- Confucius
>
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