Re: [PATCH v2 5/5] mtd: rawnand: mtk: Setup empty page threshold correctly

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Xiaolei,

Xiaolei Li <xiaolei.li@mediatek.com> wrote on Tue, 30 Apr 2019 18:02:50
+0800:

> MTK NAND Controller has the ability to check whether read data are
> mostly 0xff by comparing zero bit count of read data with empty
> threshold automatically.
> 
> But now we never set this threshold and always make it be default value
> which is 10.
> 
> This patch fixes this problem by setting empty threshold as the product
> of read sector count and ECC strength.

Are you sure it is not a per-sector value?

Did you use nandbiterrs to validate?

> 
> Fixes: 1d6b1e464950 ("mtd: mediatek: driver for MTK Smart Device")
> Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
> ---
>  drivers/mtd/nand/raw/mtk_nand.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/mtk_nand.c b/drivers/mtd/nand/raw/mtk_nand.c
> index 48759af5c058..b56965328771 100644
> --- a/drivers/mtd/nand/raw/mtk_nand.c
> +++ b/drivers/mtd/nand/raw/mtk_nand.c
> @@ -94,6 +94,7 @@
>  #define NFI_MASTER_STA		(0x224)
>  #define		MASTER_STA_MASK		(0x0FFF)
>  #define NFI_EMPTY_THRESH	(0x23C)
> +#define		EMPTY_THRESH_MASK	GENMASK(7, 0)
>  
>  #define MTK_NAME		"mtk-nand"
>  #define KB(x)			((x) * 1024UL)
> @@ -947,6 +948,14 @@ static int mtk_nfc_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
>  		return -EINVAL;
>  	}
>  
> +	/**

        /*

> +	 * Setup empty threshold as the product of sector count
> +	 * and ECC strength
> +	 */
> +	reg = sectors * chip->ecc.strength;
> +	reg = min_t(unsigned int, reg, EMPTY_THRESH_MASK);
> +	nfi_writel(nfc, reg, NFI_EMPTY_THRESH);
> +
>  	reg = nfi_readw(nfc, NFI_CNFG);
>  	reg |= CNFG_READ_EN | CNFG_DMA_BURST_EN | CNFG_AHB;
>  	if (!raw) {


Thanks,
Miquèl

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