Subject: [PATCH] MTD: at91: atmel_nand: return bit flips for the PMECC read_page()

From: [email-masked] (Josh Wu)
Date: Thu, 22 Nov 2012 11:39:58 +0800

Hi, Nicolas

On 11/21/2012 6:05 PM, Nicolas Ferre wrote:
> On 11/21/2012 06:14 AM, Josh Wu :
>>
> Can we have more comment to figure out why it is needed please?

I will add following comment in the commit message in the v2 version.

Since the commit: 3f91e94f7f511de74c0d2abe08672ccdbdd1961c ("mtd: nand: 
read_page() returns max_bitflips ()")
The ecc.read_page() method for nand drivers is changed to return the 
maximum number of bitflips instead of just returning 0.

And the nand.h is also explain that. I would like to adapt to it.

Best Regards,
Josh Wu
>
> Best regards,
>
>> Signed-off-by: Josh Wu <[email-masked]>
>> ---
>>   drivers/mtd/nand/atmel_nand.c |   13 +++++++++----
>>   1 file changed, 9 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
>> index 9144557..860dd36 100644
>> --- a/drivers/mtd/nand/atmel_nand.c
>> +++ b/drivers/mtd/nand/atmel_nand.c
>> @@ -723,6 +723,7 @@ static int pmecc_correction(struct mtd_info *mtd, u32 pmecc_stat, uint8_t *buf,
>>   	struct atmel_nand_host *host = nand_chip->priv;
>>   	int i, err_nbr, eccbytes;
>>   	uint8_t *buf_pos;
>> +	int total_err = 0;
>>   
>>   	eccbytes = nand_chip->ecc.bytes;
>>   	for (i = 0; i < eccbytes; i++)
>> @@ -750,12 +751,13 @@ normal_check:
>>   				pmecc_correct_data(mtd, buf_pos, ecc, i,
>>   					host->pmecc_bytes_per_sector, err_nbr);
>>   				mtd->ecc_stats.corrected += err_nbr;
>> +				total_err += err_nbr;
>>   			}
>>   		}
>>   		pmecc_stat >>= 1;
>>   	}
>>   
>> -	return 0;
>> +	return total_err;
>>   }
>>   
>>   static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
>> @@ -767,6 +769,7 @@ static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
>>   	uint32_t *eccpos = chip->ecc.layout->eccpos;
>>   	uint32_t stat;
>>   	unsigned long end_time;
>> +	int bitflips = 0;
>>   
>>   	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_RST);
>>   	pmecc_writel(host->ecc, CTRL, PMECC_CTRL_DISABLE);
>> @@ -789,11 +792,13 @@ static int atmel_nand_pmecc_read_page(struct mtd_info *mtd,
>>   	}
>>   
>>   	stat = pmecc_readl_relaxed(host->ecc, ISR);
>> -	if (stat != 0)
>> -		if (pmecc_correction(mtd, stat, buf, &oob[eccpos[0]]) != 0)
>> +	if (stat != 0) {
>> +		bitflips = pmecc_correction(mtd, stat, buf, &oob[eccpos[0]]);
>> +		if (bitflips < 0)
>>   			return -EIO;
>> +	}
>>   
>> -	return 0;
>> +	return bitflips;
>>   }
>>   
>>   static int atmel_nand_pmecc_write_page(struct mtd_info *mtd,
>>
>