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From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Abhishek Sahu <absahu@codeaurora.org>
Cc: Archit Taneja <architt@codeaurora.org>,
Richard Weinberger <richard@nod.at>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
Marek Vasut <marek.vasut@gmail.com>,
linux-mtd@lists.infradead.org,
Miquel Raynal <miquel.raynal@bootlin.com>,
Andy Gross <andy.gross@linaro.org>,
Brian Norris <computersforpeace@gmail.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH v2 04/14] mtd: rawnand: qcom: use the ecc strength from device parameter
Date: Mon, 7 May 2018 10:28:40 +0200 [thread overview]
Message-ID: <20180507102840.3624fe01@bbrezillon> (raw)
In-Reply-To: <1525350041-22995-5-git-send-email-absahu@codeaurora.org>
On Thu, 3 May 2018 17:50:31 +0530
Abhishek Sahu <absahu@codeaurora.org> wrote:
> Currently the driver uses the ECC strength specified in DT.
> The QPIC/EBI2 NAND supports 4 or 8-bit ECC correction. The same
> kind of board can have different NAND parts so use the ECC
> strength from device parameters if it is not specified in DT.
>
> Signed-off-by: Abhishek Sahu <absahu@codeaurora.org>
> ---
> * Changes from v1:
>
> 1. Removed the custom logic and used the helper fuction.
>
> drivers/mtd/nand/raw/qcom_nandc.c | 31 ++++++++++++++++++++++---------
> 1 file changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index b554fb6..a8d71ce 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -2315,13 +2315,21 @@ static int qcom_nand_ooblayout_free(struct mtd_info *mtd, int section,
> .free = qcom_nand_ooblayout_free,
> };
>
> +static int
> +qcom_nandc_calc_ecc_bytes(int step_size, int strength)
> +{
> + return strength == 4 ? 12 : 16;
> +}
> +NAND_ECC_CAPS_SINGLE(qcom_nandc_ecc_caps, qcom_nandc_calc_ecc_bytes,
> + NANDC_STEP_SIZE, 4, 8);
> +
> static int qcom_nand_host_setup(struct qcom_nand_host *host)
> {
> struct nand_chip *chip = &host->chip;
> struct mtd_info *mtd = nand_to_mtd(chip);
> struct nand_ecc_ctrl *ecc = &chip->ecc;
> struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
> - int cwperpage, bad_block_byte;
> + int cwperpage, bad_block_byte, ret;
> bool wide_bus;
> int ecc_mode = 1;
>
> @@ -2334,8 +2342,20 @@ static int qcom_nand_host_setup(struct qcom_nand_host *host)
> return -EINVAL;
> }
>
> + cwperpage = mtd->writesize / ecc->size;
Looks like you're still expecting nand-ecc-step-size to be defined in
the DT, which does not really make sense since you only support one
size: NANDC_STEP_SIZE.
You should remove the
if (ecc->size != NANDC_STEP_SIZE) {
dev_err(nandc->dev, "invalid ecc size\n");
return -EINVAL;
}
block, then do:
cwperpage = mtd->writesize / NANDC_STEP_SIZE;
and finally let the nand_ecc_param_setup() function choose the best
config for you.
> +
> + /*
> + * Each CW has 4 available OOB bytes which will be protected with ECC
> + * so remaining bytes can be used for ECC.
> + */
> + ret = nand_ecc_param_setup(chip, &qcom_nandc_ecc_caps,
> + mtd->oobsize - (cwperpage << 2));
Please stop doing useless optimizations like. That brings nothing and
obfuscates the code a bit more. You say in the comment that each
codeword has 4 protected OOB bytes that can be used by the upper layer,
so just do (cwperpage * 4) and let gcc optimize that for you.
> + if (ret) {
> + dev_err(nandc->dev, "No valid ecc settings possible\n");
> + return ret;
> + }
> +
> wide_bus = chip->options & NAND_BUSWIDTH_16 ? true : false;
> -
> if (ecc->strength >= 8) {
> /* 8 bit ECC defaults to BCH ECC on all platforms */
> host->bch_enabled = true;
> @@ -2403,7 +2423,6 @@ static int qcom_nand_host_setup(struct qcom_nand_host *host)
>
> mtd_set_ooblayout(mtd, &qcom_nand_ooblayout_ops);
>
> - cwperpage = mtd->writesize / ecc->size;
> nandc->max_cwperpage = max_t(unsigned int, nandc->max_cwperpage,
> cwperpage);
>
> @@ -2419,12 +2438,6 @@ static int qcom_nand_host_setup(struct qcom_nand_host *host)
> * for 8 bit ECC
> */
> host->cw_size = host->cw_data + ecc->bytes;
> -
> - if (ecc->bytes * (mtd->writesize / ecc->size) > mtd->oobsize) {
> - dev_err(nandc->dev, "ecc data doesn't fit in OOB area\n");
> - return -EINVAL;
> - }
> -
> bad_block_byte = mtd->writesize - host->cw_size * (cwperpage - 1) + 1;
>
> host->cfg0 = (cwperpage - 1) << CW_PER_PAGE
next prev parent reply other threads:[~2018-05-07 8:28 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 [this message]
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
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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