16Bit Bus with 8 Bit NAND?

[Thomas Gleixner]

On Wed, 2004-10-20 at 13:46, marcus at mikolaiczyk.de wrote:
> > > bit NAND Flash and realy don't have a clue if it's a problem that the
> > > bus reads 16 Bit from an 8 Bit NAND.
> > > 1. Does the Kernel (theh NAND Driver) automatically detect this and
> > > 'ignores' the 'empty 8 bit?
> >
> > It might work, but it's not a big deal to fix it.
> 
> Means, that it works basicly but if not I can adapt the driver
> source to work correctly?

It needs additional options and a set of additional functions for
read/write which are aware of the buswidth.

> > > 3. Or should we use 2 8bit NAND so that we've got 16bit - and is this
> > > supported in the NAND Driver?
> >
> > The 2 parallel 8bit NAND is not supported yet. Is a bit of work though.
> >
> > But why don't you use 16bit NAND ?
> 
> Is it supported with the driver for the 2.4.x Kernle Release? 'Cause we
> will use the 2.4.19 Release (an existing toolchain for tc1130 is based on
> this release).
> I read something about the supported NANDs (Toschiba,..?) in the nand.c -
> if I remember correctly. Is this strongly restricted to these NANDS
> there?

The code there is not functional at all. See also
http://www.linux-mtd.infradead.org/#kernelversions

A toolchain is neither a reason nor an excuse :)

> The colleagues, responsible for the hardware didn't tell me somenthing
> about 16 bit NAND. Mayby its size is bigger or is more expensive - I'll
> clearifiy that with the colleagues.

There are chips with e.g 32MB with either 8 or 16bit interface
available. I doubt that there is a big price difference.

tglx