linux-kernel - [PATCH v2 04/14] mtd: rawnand: qcom: use the ecc strength from device parameter

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Message-Id: <1525350041-22995-5-git-send-email-absahu@codeaurora.org>
Date:   Thu,  3 May 2018 17:50:31 +0530
From:   Abhishek Sahu <absahu@...eaurora.org>
To:     Boris Brezillon <boris.brezillon@...tlin.com>
Cc:     David Woodhouse <dwmw2@...radead.org>,
        Brian Norris <computersforpeace@...il.com>,
        Marek Vasut <marek.vasut@...il.com>,
        Richard Weinberger <richard@....at>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mtd@...ts.infradead.org, Andy Gross <andy.gross@...aro.org>,
        Archit Taneja <architt@...eaurora.org>,
        Abhishek Sahu <absahu@...eaurora.org>
Subject: [PATCH v2 04/14] mtd: rawnand: qcom: use the ecc strength from device parameter

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@...eaurora.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;
+
+	/*
+	 * 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));
+	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
-- 
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