Re: nand_imx 4k support ?

From: Baruch Siach <baruch@tkos.co.il>
To: Gabriel Tisan <gabriel.tisan@gmail.com>
Cc: barebox@lists.infradead.org
Subject: Re: nand_imx 4k support ?
Date: Mon, 2 Apr 2012 14:47:15 +0300	[thread overview]
Message-ID: <20120402114715.GB18712@sapphire.tkos.co.il> (raw)
In-Reply-To: <CAD9ZU8DG8r=6RCAieDzbjenPR_k0W-v+tjVBYV5Mvh-ntxa46w@mail.gmail.com>

Hi Gabriel,

On Mon, Apr 02, 2012 at 01:39:42PM +0200, Gabriel Tisan wrote:
> Sorry, but I didn't catch it.
> Do you mean that I don't need an OOB description for 218 byte OOB ?

If the software doing the flash write operation does not touch the OOB area in 
any way, than OOB layout description is not needed. The Linux kernel needs 
this layout information for the reasons stated in the 2c1c5f199 commit log.  
This reason apparently, is not applicable to Barebox as is evident from the 
experience of Eric.

However, since OOB layout description tables for 512B and 2k page sizes, it 
seems that this information is useful in some scenarios.

baruch

> On Mon, Apr 2, 2012 at 1:30 PM, Baruch Siach <baruch@tkos.co.il> wrote:
> > Hi Gabriel,
> >
> > On Mon, Apr 02, 2012 at 11:03:06AM +0200, Gabriel Tisan wrote:
> >> Yes, Baruch I meant write support, especially ECC layout for 4K flashes.
> >>
> >> Actually the 4k flashes could have 128 or 218 bytes OOB.
> >>
> >> Could you point me to some docs about this layout ? I use a flash with
> >> 218 bytes spare.
> >
> > See commit 2c1c5f199 of the Linux kernel at
> > http://git.kernel.org/linus/2c1c5f199.
> >
> > As Eric has pointed out, this may not be necessary for Barebox.
> >
> > baruch
> >
> >> On Sun, Apr 1, 2012 at 3:05 PM, Eric Bénard <eric@eukrea.com> wrote:
> >> > Le Sun, 1 Apr 2012 15:52:09 +0300,
> >> > Baruch Siach <baruch@tkos.co.il> a écrit :
> >> >> Does the Linux kernel detect your flash correctly?
> >> >>
> >> > I'm not at this stage for the moment as I'm using a SDcard rootfs to
> >> > validate the hardware for the moment, but I'm sure the actual problem
> >> > (in my case at least) in barebox is a detection problem as I get the
> >> > right values from the flash but these value are ONFI and thus are not
> >> > right with he actual flash detection code which leads to a wrong
> >> > configuration of the NFC. Once I hardcode the NFC settings I manage to
> >> > read/write in the 4k NAND Flash from barebox (environment & kernel
> >> > are in the flash for the moment).

-- 
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

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