From: Abhishek Sahu <absahu@codeaurora.org>
To: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>,
David Woodhouse <dwmw2@infradead.org>,
Brian Norris <computersforpeace@gmail.com>,
Marek Vasut <marek.vasut@gmail.com>,
Richard Weinberger <richard@nod.at>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mtd@lists.infradead.org, Andy Gross <andy.gross@linaro.org>,
Archit Taneja <architt@codeaurora.org>
Subject: Re: [PATCH v2 09/14] mtd: rawnand: qcom: modify write_oob to remove read codeword part
Date: Tue, 22 May 2018 19:44:54 +0530 [thread overview]
Message-ID: <ec5063fab29afb218e7de436384b8b43@codeaurora.org> (raw)
In-Reply-To: <20180522120231.5dd32f8b@xps13>
On 2018-05-22 15:32, Miquel Raynal wrote:
> Hi Abhishek,
>
> Some nitpicking below.
>
> On Thu, 3 May 2018 17:50:36 +0530, Abhishek Sahu
> <absahu@codeaurora.org> wrote:
>
>> QCOM NAND layout protect available OOB data bytes with ECC also so
>
> ^controller
>
>> when ecc->write_oob (qcom_nandc_write_oob) is being called then it
>
> You can just state "->write_oob()"
>
>> can't update just OOB bytes. Currently, it first reads the last
>> codeword which includes old OOB bytes. Then it updates the old OOB
>> bytes with new one and then again writes the codeword back.
>
> ones?
>
>> The reading codeword is unnecessary since all the other bytes
>> should be 0xff only.
>
> since the user is responsible to
> have these bytes cleared to 0xFF.
>
>>
>> This patch removes the read part and updates the oob bytes with
>
> s/oob/OOB/
>
>> all other data bytes as 0xff.
>
> The end of the sentence is not clear for me. Do you mean that padding
> with 0xFF is realized before write?
>
>>
>> Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
>> ---
>> * Changes from v1:
>>
>> NEW CHANGE
>>
>> drivers/mtd/nand/raw/qcom_nandc.c | 17 +++++------------
>> 1 file changed, 5 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c
>> b/drivers/mtd/nand/raw/qcom_nandc.c
>> index 61d0e7d..f85d8ab 100644
>> --- a/drivers/mtd/nand/raw/qcom_nandc.c
>> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
>> @@ -2067,10 +2067,9 @@ static int qcom_nandc_write_page_raw(struct
>> mtd_info *mtd,
>> * implements ecc->write_oob()
>> *
>> * the NAND controller cannot write only data or only oob within a
>> codeword,
>
> s/oob/OOB/
>
> Remove the trailing ','
>
>> - * since ecc is calculated for the combined codeword. we first copy
>> the
>> - * entire contents for the last codeword(data + oob), replace the old
>> oob
>> - * with the new one in chip->oob_poi, and then write the entire
>> codeword.
>> - * this read-copy-write operation results in a slight performance
>> loss.
>> + * since ecc is calculated for the combined codeword. So make all the
>> data
>
> s/ecc/ECC/
>
>> + * bytes as 0xff and update the oob from chip->oob_poi, and then
>> write
>> + * the entire codeword again.
>
> What about "Pad the data area with OxFF before writing."?
>
>> */
>> static int qcom_nandc_write_oob(struct mtd_info *mtd, struct
>> nand_chip *chip,
>> int page)
>> @@ -2082,20 +2081,14 @@ static int qcom_nandc_write_oob(struct
>> mtd_info *mtd, struct nand_chip *chip,
>> int data_size, oob_size;
>> int ret;
>>
>> - host->use_ecc = true;
>> -
>> - clear_bam_transaction(nandc);
>> - ret = copy_last_cw(host, page);
>> - if (ret)
>> - return ret;
>> -
>> - clear_read_regs(nandc);
>> clear_bam_transaction(nandc);
>>
>> /* calculate the data and oob size for the last codeword/step */
>> data_size = ecc->size - ((ecc->steps - 1) << 2);
>> oob_size = mtd->oobavail;
>> + host->use_ecc = true;
>
> You don't need to move this line here, do you?
>
>>
>> + memset(nandc->data_buffer, 0xff, host->cw_data);
>> /* override new oob content to last codeword */
>> mtd_ooblayout_get_databytes(mtd, nandc->data_buffer + data_size,
>> oob,
>> 0, mtd->oobavail);
>
>
> Once fixed, you can add my:
Thanks Miquel.
I will fix all these and update the patch.
Regards,
Abhishek
>
> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
>
> Thanks,
> Miquèl
next prev parent reply other threads:[~2018-05-22 14:14 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-03 12:20 [PATCH v2 00/14] Update for QCOM NAND driver Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 01/14] mtd: rawnand: helper function for setting up ECC parameters Abhishek Sahu
2018-05-07 3:40 ` Masahiro Yamada
2018-05-07 6:01 ` Abhishek Sahu
2018-05-07 7:39 ` Boris Brezillon
2018-05-08 6:14 ` Masahiro Yamada
2018-05-08 7:21 ` Abhishek Sahu
2018-05-07 8:16 ` Boris Brezillon
2018-05-08 7:22 ` Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 02/14] mtd: rawnand: denali: use helper function for ecc setup Abhishek Sahu
2018-05-21 14:30 ` Miquel Raynal
2018-05-22 14:09 ` Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 03/14] dt-bindings: qcom_nandc: make nand-ecc-strength optional Abhishek Sahu
2018-05-07 8:40 ` Boris Brezillon
2018-05-21 14:32 ` Miquel Raynal
2018-05-22 14:08 ` Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 04/14] mtd: rawnand: qcom: use the ecc strength from device parameter Abhishek Sahu
2018-05-07 8:28 ` Boris Brezillon
2018-05-08 7:26 ` Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 05/14] mtd: rawnand: qcom: wait for desc completion in all BAM channels Abhishek Sahu
2018-05-22 6:47 ` Miquel Raynal
2018-05-22 14:07 ` Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 06/14] mtd: rawnand: qcom: erased page detection for uncorrectable errors only Abhishek Sahu
2018-05-22 7:04 ` Miquel Raynal
2018-05-22 14:10 ` Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 07/14] mtd: rawnand: qcom: fix null pointer access for erased page detection Abhishek Sahu
2018-05-22 7:16 ` Miquel Raynal
2018-05-22 14:11 ` Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 08/14] mtd: rawnand: qcom: parse read errors for read oob also Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 09/14] mtd: rawnand: qcom: modify write_oob to remove read codeword part Abhishek Sahu
2018-05-22 10:02 ` Miquel Raynal
2018-05-22 14:14 ` Abhishek Sahu [this message]
2018-05-03 12:20 ` [PATCH v2 10/14] mtd: rawnand: qcom: fix return value for raw page read Abhishek Sahu
2018-05-22 12:04 ` Miquel Raynal
2018-05-22 14:15 ` Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 11/14] mtd: rawnand: qcom: minor code reorganization for bad block check Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 12/14] mtd: rawnand: qcom: check for operation errors in case of raw read Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 13/14] mtd: rawnand: qcom: helper function for " Abhishek Sahu
2018-05-03 12:20 ` [PATCH v2 14/14] mtd: rawnand: qcom: erased page bitflips detection Abhishek Sahu
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