Re: [PATCH] Add driver for M-sys / Sandisk diskonchip G4 nand flash

[Marek Vasut <marek.vasut@gmail.com>]

On Wednesday, October 12, 2011 11:28:34 PM Robert Jarzmik wrote:
> Mike Dunn <mikedunn@newsguy.com> writes:
> > This is a driver for the diskonchip G4 in my Palm Treo680.  I've tested
> > it fairly well; it passes the nandtest utility, and I've been able to
> > create a ubifs using it.
> 
> Hi Mike,
> 
Hi Robert,

> I had a look at your driver, to see how close it was to the docg3 I
> submitted before and if we could share some code.
> 
> My feeling is that the 2 chips are a bit different, and that the deserve
> each a separate driver, until one can manage them both (if that ever is
> possible). The discrepencies I noticed are :
>  - docg4 doesn't need to write to an "address register" before reading some
>  random register (ie. between io+0x1000 and io+0x1800), docg3 needs it

This can be done on both ...

>  - docg4 adressing is larger (4 bytes against 3 in docg3)

if (drvdata->version == 4) {} ?

>  - docg4 adressing is different (the calculation 0x108 * page_number),
> while docg3 is more straight forward (0x100 * page)

See above ... you can determine if it's G3 or G4 by version register iirc ?

>  - in docg4 driver, I didn't see the "2 pages per block notion". I think
> it's there, but I couldn't find it
>  - some read/write sequences are different, with different registers, and
> with additionnal reads in your case (ie. the MYSTERY register for
> example).

This can be done on G3 too?

> 
> The good part is that I think we share the same registers, although you
> seem to have more of them. And I think the BCH algorithm is the same, and
> I'm really interested in the outcome of your work with Ivan.
> 
> Therefore, I'll help review your driver as much as I can, so that you can
> merge it in mainline.
>

Definitelly looking forward to this too. I can try on PalmT5 if you like, it 
SHOULD have a G3. You can also prep me a testing patch on top of this one which 
would add support for G3 and I can test that too.

Cheers