[PATCH] nand gpmi fix erased block bitflip counting

[Marek Vasut]

On 11/09/2016 01:35 PM, w.cappelle at televic.com wrote:
> From: Wouter Cappelle <w.cappelle at televic.com>

Please add commit message explaining the purpose of the patch.
CCing some more interested people.

> ---
>  drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> index 8339d4f..6ae118c 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> @@ -1217,6 +1217,7 @@ static bool gpmi_erased_check(struct gpmi_nand_data *this,
>  	int base = geo->ecc_chunkn_size * chunk;
>  	unsigned int flip_bits = 0, flip_bits_noecc = 0;
>  	uint64_t *buf = (uint64_t *)this->data_buffer_dma;
> +	unsigned char *chunkbuf =(unsigned char*) this->data_buffer_dma;
>  	unsigned int threshold;
>  	int i;
>  
> @@ -1224,13 +1225,6 @@ static bool gpmi_erased_check(struct gpmi_nand_data *this,
>  	if (threshold > geo->ecc_strength)
>  		threshold = geo->ecc_strength;
>  
> -	/* Count bitflips */
> -	for (i = 0; i < geo->ecc_chunkn_size; i++) {
> -		flip_bits += hweight8(~data[base + i]);
> -		if (flip_bits > threshold)
> -			return false;
> -	}
> -
>  	/*
>  	 * Read out the whole page with ECC disabled, and check it again,
>  	 * This is more strict then just read out a chunk, and it makes
> @@ -1246,6 +1240,12 @@ static bool gpmi_erased_check(struct gpmi_nand_data *this,
>  			return false;
>  	}
>  
> +	/* Count bitflips in the current chunk for correct stats reporting */
> +	for (i = 0; i < geo->ecc_chunkn_size; i++) {
> +		flip_bits += hweight8(~chunkbuf[base + i]);
> +	}
> +
> +
>  	/* Tell the upper layer the bitflips we corrected. */
>  	mtd->ecc_stats.corrected += flip_bits;
>  	*max_bitflips = max_t(unsigned int, *max_bitflips, flip_bits);
> 


-- 
Best regards,
Marek Vasut