Re: 16Bit Bus with 8 Bit NAND?

Re: 16Bit Bus with 8 Bit NAND?

[Thomas Gleixner]

On Wed, 2004-10-20 at 13:46, marcus@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

16Bit Bus with 8 Bit NAND?

[marcus]

Hi everybody,
I'm new to the embedded technologie and have a question concerning a setup
that uses the Infineon TC1130 (Microcontroller) together with NAND Flash.

The situation is that the TC1130 has an 16Bit EBU (External Bus Unit) to
connect to Flash, Disc On Chip, etc. devices. We disscuss the usage of 8
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.
The question is, what setup should be used to get this with Linux
working.
1. Does the Kernel (theh NAND Driver) automatically detect this and
'ignores' the 'empty 8 bit?
2. Or is it somehow configruable in the Driver befor comilation?
3. Or should we use 2 8bit NAND so that we've got 16bit - and is this
supported in  the NAND Driver?

I searched in the archive and found one note *) but only for 32 bit 8 bit,
and unfortunately with a 'hack' . 


*) "JFFS2 on big-endian system, 8-bit wide flash on 32-bit bus." 15.april
2004 , Joshua Lasmorie

Please help.

Best regards

Marcus Mikolaiczyk

Re: 16Bit Bus with 8 Bit NAND?

[Thomas Gleixner]

On Wed, 2004-10-20 at 10:52, marcus@mikolaiczyk.de wrote:
> Hi everybody,
> I'm new to the embedded technologie and have a question concerning a setup
> that uses the Infineon TC1130 (Microcontroller) together with NAND Flash.
> 
> The situation is that the TC1130 has an 16Bit EBU (External Bus Unit) to
> connect to Flash, Disc On Chip, etc. devices. We disscuss the usage of 8
> 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.
> The question is, what setup should be used to get this with Linux
> working.
> 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.

> 2. Or is it somehow configruable in the Driver befor comilation?

When it's fixed, it will be a option from the baord driver

> 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 ? 

tglx