Re: [PATCHv4 1/1] mtd: nand: pxa3xx: Set FORCE_CSX bit to ARMADA370 variants

[Chris Packham]

Hi Miquel, Ezequiel,

On 23/12/17 05:56, Ezequiel Garcia wrote:
> On 22 December 2017 at 12:53, Miquel RAYNAL
> <miquel.raynal@xxxxxxxxxxxxxxxxxx> wrote:
>> Hello Chris,
>>
>> On Fri, 22 Dec 2017 12:19:04 +1300
>> Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx> wrote:
>>
>>> From: Kalyan Kinthada <kalyan.kinthada@xxxxxxxxxxxxxxxxxxx>
>>>
>>> The Armada-370 based SoCs support arbitration between the NAND Flash
>>> interface and NOR (i.e. devbus) on the same chip select. However there
>>> are two guidelines that must be followed to avoid data corruption in
>>> this scenario.
>>
>> Sorry to bother you again with that but, do you actually face any
>> issue/data corruption with this scenario?
>>
> 
> Indeed. We need a description of a real world problem this patch is fixing.
> 

I totally agree. The Marvell FAE used words like "data corruption" hence 
my re-newed interest in this. I had hoped these patches would pique the 
interest of someone from Marvell's engineering team with some more info 
on how the data corruption exhibits.

I've been running some of the mtd-utils tests on my hardware and haven't 
detected any failures yet.

I think the key would be to be doing interleaved accesses between nand 
and the parallel device. I've just kicked off something I think should 
do this on my hardware but I'm unsure as to how long I should wait for 
an issue to present itself.

I'll leave it running for as long as I can today. If I find a failure 
I'll report back otherwise we can leave this patch for the mailing list 
archives waiting for an issue to be seen.