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Date:   Wed, 26 Jun 2019 08:48:07 +0200
From:   Boris Brezillon <boris.brezillon@collabora.com>
To:     Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
Cc:     miquel.raynal@bootlin.com, helmut.grohne@intenta.de,
        richard@nod.at, dwmw2@infradead.org, computersforpeace@gmail.com,
        marek.vasut@gmail.com, vigneshr@ti.com, bbrezillon@kernel.org,
        yamada.masahiro@socionext.com, linux-mtd@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: Re: [LINUX PATCH v17 1/2] mtd: rawnand: nand_micron: Do not over
 write driver's read_page()/write_page()
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On Mon, 24 Jun 2019 22:46:29 -0600
Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com> wrote:

> Add check before assigning chip->ecc.read_page() and chip->ecc.write_page()
> 
> Signed-off-by: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
> ---
>  drivers/mtd/nand/raw/nand_micron.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/nand_micron.c b/drivers/mtd/nand/raw/nand_micron.c
> index cbd4f09ac178..565f2696c747 100644
> --- a/drivers/mtd/nand/raw/nand_micron.c
> +++ b/drivers/mtd/nand/raw/nand_micron.c
> @@ -500,8 +500,11 @@ static int micron_nand_init(struct nand_chip *chip)
>  		chip->ecc.size = 512;
>  		chip->ecc.strength = chip->base.eccreq.strength;
>  		chip->ecc.algo = NAND_ECC_BCH;
> -		chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
> -		chip->ecc.write_page = micron_nand_write_page_on_die_ecc;
> +		if (!chip->ecc.read_page)
> +			chip->ecc.read_page = micron_nand_read_page_on_die_ecc;
> +
> +		if (!chip->ecc.write_page)
> +			chip->ecc.write_page = micron_nand_write_page_on_die_ecc;

That's wrong, if you don't want on-die ECC to be used, simply don't set
nand-ecc-mode to "on-die".

>  
>  		if (ondie == MICRON_ON_DIE_MANDATORY) {
>  			chip->ecc.read_page_raw = nand_read_page_raw_notsupp;