Re: [PATCH v2 06/14] mtd: rawnand: qcom: erased page detection for uncorrectable errors only

[Abhishek Sahu]

On 2018-05-22 12:34, Miquel Raynal wrote:
> Hi Abhishek,
>
> On Thu,  3 May 2018 17:50:33 +0530, Abhishek Sahu
> <absahu@xxxxxxxxxxxxxx> wrote:
>
> > Following is the flow in the HW if controller tries to read erased
> > page
>
> Nit:  ^ missing ':'

 Sure. I will fix this.

> > 1. First ECC uncorrectable error will be generated from ECC engine
> >    since ECC engine first calculates the ECC with all 0xff and match
> >    the calculated ECC with ECC code in OOB (which is again all 0xff).
> > 2. After getting ECC error, erased CW detection logic will be
> >    applied which is different for BCH and RS ECC
> >     a. For BCH, HW checks if all the bytes in page are 0xff and then
> >        it updates the status in separate register
> >        NAND_ERASED_CW_DETECT_STATUS.
> >     b. For RS ECC, the HW reports the same error when reading an
> >        erased CW, but it notifies that it is an erased CW by
> >        placing special characters at certain offsets in the
> >        buffer.
> >
> > So the erased CW detect status should be checked only if ECC engine
> > generated the uncorrectable error.
> >
> > Currently for all other operational errors also (like TIMEOUT, MPU
> > errors, etc.), the erased CW detect logic is being applied so fix this
> > and return EIO for other operational errors.
> >
> > Signed-off-by: Abhishek Sahu <absahu@xxxxxxxxxxxxxx>
> > ---
> > * Changes from v1:
> >
> >   1. Added more detail in commit message
> >   2. Added comment before each if/else
>
> Thanks for that, it's much more ease to review :)

 Thanks Miquel for your review.

 Regards,
 Abhishek

> >   3. Removed redundant check for BS_UNCORRECTABLE_BIT
> >
> >  drivers/mtd/nand/raw/qcom_nandc.c | 65 
> > ++++++++++++++++++++++++++-------------
> >  1 file changed, 43 insertions(+), 22 deletions(-)
>
> Acked-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
>
> Thanks,
> MiquÃl