[U-Boot] flash post test

[Scott Wood]

On 02/06/2012 04:23 PM, Albert ARIBAUD wrote:
> Hi Vaibhav,
> 
> Le 06/02/2012 05:57, vaibhav kothari a écrit :
>> hi albert
>>
>> Yes,actually there is already support of flash test in POST of latest
>> uboot.They are testing flash on every power on so am I for my board.But i
>> don't want to disturb sectors in which uboot code relies. Can you help me
>> here?
> 
> I am no NAND specialist, but I do hope NAND POST tests are pure read
> tests and thus are not affected by poweroffs (and can actually test any
> part of NAND).

NAND has a property called "read disturb", where excessively reading a
sector without writing to it can eventually cause data loss.  U-Boot is
already read once per boot, but reading it a second time could halve the
expected lifetime.  Data managed by something like ubi is be scrubbed in
a way that avoids this, but U-Boot itself is not usually managed in this
way (boot hardware/rom does not understand ubi).

-Scott