Re: [PATCH v7 2/2] mtd: rawnand: meson: add support for Amlogic NAND flash controller

[Miquel Raynal <miquel.raynal@xxxxxxxxxxx>]

Hi Liang,

Liang Yang <liang.yang@xxxxxxxxxxx> wrote on Mon, 10 Dec 2018 20:12:39
+0800:

> On 2018/12/10 19:38, Boris Brezillon wrote:
> > On Mon, 10 Dec 2018 19:23:46 +0800
> > Liang Yang <liang.yang@xxxxxxxxxxx> wrote:
> >   
> >>>> +			mtd->ecc_stats.failed++;
> >>>> +			continue;
> >>>> +		}
> >>>> +		mtd->ecc_stats.corrected += ECC_ERR_CNT(*info);
> >>>> +		bitflips = max_t(u32, bitflips, ECC_ERR_CNT(*info));
> >>>> +	}  
> >>>
> >>> Are you sure you handle correctly empty pages with bf?  
> >>>    >> if scramble is enable, i would say yes here.  
> >> when scramble is disabled, i am considering how to use the helper
> >> nand_check_erased_ecc_chunk, but it seems that i can't get the ecc
> >> bytes which is caculated by ecc engine.by the way, nfc dma doesn't send
> >> out the ecc parity bytes.  
> > 
> > Even if the ECC engine is disabled?
> >   
> No.
> When ECC engine is disabled, it can read the ecc parity bytes ; but there is another problem that i need to consider how code struct looks better when reading error with ecc opened and then try to raw read.
> Is there a good idea?

When reading with ECC enabled, in case of uncorrectable error you
must re-read without ECC, then check if the page is empty or not with
the core helpers (nand_check_erased_*()).

Is this what you meant?

Thanks,
Miquèl

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