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From:   Kamal Dasu <kdasu.kdev@gmail.com>
To:     linux-mtd@lists.infradead.org
Cc:     bcm-kernel-feedback-list@broadcom.com,
        linux-kernel@vger.kernel.org, Kamal Dasu <kdasu.kdev@gmail.com>,
        Brian Norris <computersforpeace@gmail.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        David Woodhouse <dwmw2@infradead.org>,
        Marek Vasut <marek.vasut@gmail.com>,
        Vignesh Raghavendra <vigneshr@ti.com>
Subject: [PATCH v2 2/2] mtd: nand: raw: brcmnand: fallback to detected ecc-strength, ecc-step-size
Date:   Mon, 20 May 2019 15:05:12 -0400
Message-Id: <1558379144-28283-2-git-send-email-kdasu.kdev@gmail.com>
In-Reply-To: <1558379144-28283-1-git-send-email-kdasu.kdev@gmail.com>
References: <1558379144-28283-1-git-send-email-kdasu.kdev@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
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This change supports nand-ecc-step-size and nand-ecc-strength fields in
brcmnand DT node to be optional.
see: Documentation/devicetree/bindings/mtd/brcm,brcmnand.txt

If both nand-ecc-strength and nand-ecc-step-size are not specified in
device tree node for NAND, raw NAND layer does detect ECC information by
reading ONFI extended parameter page for parts using ONFI >= 2.1.
In case of non-ONFI NAND parts there could be a nand_id table entry with
ECC information. If there is valid device tree entry for nand-ecc-strength
and nand-ecc-step-size fields it still shall override the detected values.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
---
 drivers/mtd/nand/raw/brcmnand/brcmnand.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index ce0b8ff..a4d2057 100644
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -2144,6 +2144,17 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
 		return -EINVAL;
 	}
 
+	if (chip->ecc.mode != NAND_ECC_NONE &&
+	    (!chip->ecc.size || !chip->ecc.strength)) {
+		if (chip->base.eccreq.step_size && chip->base.eccreq.strength) {
+			/* use detected ECC parameters */
+			chip->ecc.size = chip->base.eccreq.step_size;
+			chip->ecc.strength = chip->base.eccreq.strength;
+			pr_info("Using ECC step-size %d, strength %d\n",
+				chip->ecc.size, chip->ecc.strength);
+		}
+	}
+
 	switch (chip->ecc.size) {
 	case 512:
 		if (chip->ecc.algo == NAND_ECC_HAMMING)
-- 
1.9.0.138.g2de3478