Doubt regarding mtd test ( mtd_oobtest ) interpretation of oob data !

[Murali N]

Hi Artem, can you please explain me a bit more about OOB_PLACE mode?.
Also in mtd tests i have seen there is ooboffs field being used in
OOB_AUTO mode.My doubt here was why AUTO mode cares about ooboffs
field.ECC layout structure is defined clearly in the AUTO mode? am i
correct? then what is the significance of ooboffs field?

i am not caring the ooboffs when the AUTO mode is selected in my
driver? i was bit confused where it is mentioned in the MTD
specification? can you please point to me if you have any info!!!

thanks

On Wed, Sep 16, 2009 at 3:06 PM, Artem Bityutskiy <dedekind1 at gmail.com> wrote:
> On Wed, 2009-09-16 at 12:39 +0530, Murali N wrote:
>> Hi All,
>> i have a doubt on how the OOB data is being managed in MTD driver.
>> Recently i have enabled mtd-tests to test my driver for mtd
>> compliance.After i ran "mtd_oobtest" i was messed up with test and
>> come up with few questions:
>>
>> 1) Is these tests are well validated? can i trust these tests 100%
>> compliant to MTD API specification?
>> 2) In "mtd_oobtest" ( drivers/mtd/tests/ ), there was a "test 4 of 5"
>> in this there was a few checks for writing/reading end off OOB data.
>>             - In these tests what is the significance of using
>> "ooboffs" in OOB_AUTO mode?
>> 3) Is MTD driver ask the below NAND driver to read/write the oob data
>> integral of oobavail size in OOB_AUTO mode? How MTD driver behaves if
>> it is not!!!
>> 4) Finally, can anyone please explain bit more about OOB_PLACE mode?
>> also the significance of ooboffs field usage?
>
> I do not understand your questions, and I do not quite remember these
> modes already, but the below code probably explains things well:
>
> /*
>  * oob operation modes
>  *
>  * MTD_OOB_PLACE:       oob data are placed at the given offset
>  * MTD_OOB_AUTO:        oob data are automatically placed at the free
> areas
>  *                      which are defined by the ecclayout
>  * MTD_OOB_RAW:         mode to read raw data+oob in one chunk. The oob
> data
>  *                      is inserted into the data. Thats a raw image of
> the
>  *                      flash contents.
>  */
> typedef enum {
>        MTD_OOB_PLACE,
>        MTD_OOB_AUTO,
>        MTD_OOB_RAW,
> } mtd_oob_mode_t;
>
> --
> Best Regards,
> Artem Bityutskiy (Артём Битюцкий)
>
>



-- 
Regards,
Murali N