Re: [PATCH] mtd: nand: gpmi: add proper raw access support

From: Boris Brezillon
Date: Tue Sep 30 2014 - 04:04:32 EST

Hi Iwo,

On Mon, 29 Sep 2014 11:22:11 +1000
Iwo Mergler <Iwo.Mergler@xxxxxxxxxxxxxxxxxxx> wrote:

> On Thu, 11 Sep 2014 22:36:16 +1000
> Boris BREZILLON <boris.brezillon@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > Well, I don't know about freescale specific tools, but at least I have
> > an example with mtd_nandbiterrs module.
> > This module is assuming it can write only the data part of a NAND page
> > without modifying the OOB area (see [1]), which in GPMI controller
> > case is impossible because raw write function store the data as if
> > there were no specific scheme, while there is one:
> > (metadata + n x (data_chunk + ECC bytes) + remaining_bytes).
> >
> Hi Boris,
> just as an aside, only the incremental bit errors test in nandbiterrs
> positively requires raw data write.
> The overwrite test (re-write the same page data repeatedly without
> erase), only uses raw access because I was lazy. A normal ECC write
> would do just as well.

Anyway, the test I'm really interested in is the incremental bit errors
test :-).

BTW, any reason you chose to implement this test/testsuite as a
module ?
>From my understanding (and tell me if I'm wrong) we could do the same
from user-space.

Best Regards,


Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
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