Re: [PATCH v2 11/53] mtd: nand: denali: fix bitflips calculation in handle_ecc()

Masahiro Yamada
2017-03-23T07:02:42Z

Hi Boris,

2017-03-23 5:57 GMT+09:00 Boris Brezillon <boris.brezillon@free-electrons.com>:
> On Wed, 22 Mar 2017 23:07:18 +0900
> Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>
>> + do {
>> + err_addr = ioread32(denali->flash_reg + ECC_ERROR_ADDRESS);
>> + err_sector = ECC_SECTOR(err_addr);
>> + err_byte = ECC_BYTE(err_addr);
>> +
>> + err_cor_info = ioread32(denali->flash_reg + ERR_CORRECTION_INFO);
>> + err_cor_value = ECC_CORRECTION_VALUE(err_cor_info);
>> + err_device = ECC_ERR_DEVICE(err_cor_info);
>> +
>> + /* reset the bitflip counter when crossing ECC sector */
>> + if (err_sector != prev_sector)
>> + bitflips = 0;
>> +
>> + if (ECC_ERROR_UNCORRECTABLE(err_cor_info)) {
>> + /*
>> + * if the error is not correctable, need to look at the
>> + * page to see if it is an erased page. if so, then
>> + * it's not a real ECC error
>> + */
>> + ret = -EBADMSG;
>
> You should never return -EBADMSG directly. Just increment
> ecc_stats.failed and let the core return -EBADMSG to the upper layer.
>

Here, -EBADMSG is used like that returned from ->ecc.correct()

Please notice denali_read_page() never returns -EBADMSG.

-EBADMSG is used as a mark "we need erased page check".

I think nand_read_page_syndrome() does similar;
-EBADMSG is used internally.

--
Best Regards
Masahiro Yamada