Re: [PATCH v5 1/3] mtd: nand: don't select chip in nand_chip's block_bad op

[Archit Taneja <architt@codeaurora.org>]

On 01/06/2016 09:35 PM, Boris Brezillon wrote:
> On Tue,  5 Jan 2016 10:54:59 +0530
> Archit Taneja <architt@codeaurora.org> wrote:
>
>> One of the arguments passed to struct nand_chip's block_bad op is
>> 'getchip', which, if true, is supposed to get and select the nand device,
>> and later unselect and release the device.
>>
>> This op is intended to be replaceable by drivers. The drivers shouldn't
>> be responsible for selecting/unselecting chip. Like other ops, the chip
>> should already be selected before the block_bad op is called.
>>
>> Remove the getchip argument from the block_bad op and move the chip
>> selection to nand_block_checkbad (the only user of chip->block_bad).
>> Modify nand_block_bad (the default function for the op) such that
>> it doesn't select the chip.
>
> I would go even further and move the chip selection into
> nand_block_isbad(), who is the only caller that requires this chip
> selection.

You're right. The only other place where nand_block_checkbad is used is
nand_erase_nand, and that already selects the chip before.

I'll update the patch.

Thanks,
Archit

>
>>
>> Signed-off-by: Archit Taneja <architt@codeaurora.org>
>> ---
>>   drivers/mtd/nand/nand_base.c | 41 +++++++++++++++++++++++------------------
>>   include/linux/mtd/nand.h     |  2 +-
>>   2 files changed, 24 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
>> index 928081b..42aa441 100644
>> --- a/drivers/mtd/nand/nand_base.c
>> +++ b/drivers/mtd/nand/nand_base.c
>> @@ -317,9 +317,9 @@ static void nand_read_buf16(struct mtd_info *mtd, uint8_t *buf, int len)
>>    *
>>    * Check, if the block is bad.
>>    */
>> -static int nand_block_bad(struct mtd_info *mtd, loff_t ofs, int getchip)
>> +static int nand_block_bad(struct mtd_info *mtd, loff_t ofs)
>>   {
>> -	int page, chipnr, res = 0, i = 0;
>> +	int page, res = 0, i = 0;
>>   	struct nand_chip *chip = mtd_to_nand(mtd);
>>   	u16 bad;
>>
>> @@ -328,15 +328,6 @@ static int nand_block_bad(struct mtd_info *mtd, loff_t ofs, int getchip)
>>
>>   	page = (int)(ofs >> chip->page_shift) & chip->pagemask;
>>
>> -	if (getchip) {
>> -		chipnr = (int)(ofs >> chip->chip_shift);
>> -
>> -		nand_get_device(mtd, FL_READING);
>> -
>> -		/* Select the NAND device */
>> -		chip->select_chip(mtd, chipnr);
>> -	}
>> -
>>   	do {
>>   		if (chip->options & NAND_BUSWIDTH_16) {
>>   			chip->cmdfunc(mtd, NAND_CMD_READOOB,
>> @@ -361,11 +352,6 @@ static int nand_block_bad(struct mtd_info *mtd, loff_t ofs, int getchip)
>>   		i++;
>>   	} while (!res && i < 2 && (chip->bbt_options & NAND_BBT_SCAN2NDPAGE));
>>
>> -	if (getchip) {
>> -		chip->select_chip(mtd, -1);
>> -		nand_release_device(mtd);
>> -	}
>> -
>>   	return res;
>>   }
>>
>> @@ -514,8 +500,27 @@ static int nand_block_checkbad(struct mtd_info *mtd, loff_t ofs, int getchip,
>>   {
>>   	struct nand_chip *chip = mtd_to_nand(mtd);
>>
>> -	if (!chip->bbt)
>> -		return chip->block_bad(mtd, ofs, getchip);
>> +	if (!chip->bbt) {
>> +		int ret;
>> +
>> +		if (getchip) {
>> +			int chipnr = (int)(ofs >> chip->chip_shift);
>> +
>> +			nand_get_device(mtd, FL_READING);
>> +
>> +			/* Select the NAND device */
>> +			chip->select_chip(mtd, chipnr);
>> +		}
>> +
>> +		ret = chip->block_bad(mtd, ofs);
>> +
>> +		if (getchip) {
>> +			chip->select_chip(mtd, -1);
>> +			nand_release_device(mtd);
>> +		}
>> +
>> +		return ret;
>> +	}
>>
>>   	/* Return info from the table */
>>   	return nand_isbad_bbt(mtd, ofs, allowbbt);
>> diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
>> index 3e92be1..c15818e 100644
>> --- a/include/linux/mtd/nand.h
>> +++ b/include/linux/mtd/nand.h
>> @@ -650,7 +650,7 @@ struct nand_chip {
>>   	void (*write_buf)(struct mtd_info *mtd, const uint8_t *buf, int len);
>>   	void (*read_buf)(struct mtd_info *mtd, uint8_t *buf, int len);
>>   	void (*select_chip)(struct mtd_info *mtd, int chip);
>> -	int (*block_bad)(struct mtd_info *mtd, loff_t ofs, int getchip);
>> +	int (*block_bad)(struct mtd_info *mtd, loff_t ofs);
>>   	int (*block_markbad)(struct mtd_info *mtd, loff_t ofs);
>>   	void (*cmd_ctrl)(struct mtd_info *mtd, int dat, unsigned int ctrl);
>>   	int (*dev_ready)(struct mtd_info *mtd);
>
>
>

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