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

From: Liang Yang
Date: Mon Dec 10 2018 - 20:56:18 EST

Hi Miquel,

On 2018/12/10 22:50, Miquel Raynal wrote:
Hi Liang,

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

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 the way, nfc dma doesn't send
out the ecc parity bytes.

Even if the ECC engine is disabled?
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?

yes. when uncorrectable ECC error, i need firstly read out the ECC bytes without ECC engine and then use the helper nand_check_erased_ecc_chunk to check if blank page.
Of course, the precondition is without scrambler, or the bland page can be detected by meson NFC.