Re: [PATCH v2 13/19] mtd: rawnand: cafe: Don't split things when reading/writing a page

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

Boris Brezillon <boris.brezillon@collabora.com> wrote on Tue,  5 May
2020 12:13:47 +0200:

> Calling nand_read_page_op(pagesize)/nand_prog_page_begin_op(pagesize)
> and expecting to get a pagesize+oobsize read from/written to the
> read/write buffer is fragile and only works because of hacks done
> in cmdfunc(). Let's read/write the page in one go, using the page
> cache buffer as a bounce buffer instead of relying on guesses done
> in cafe_nand_cmdfunc().
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> Tested-by: Lubomir Rintel <lkundrak@v3.sk>
> ---
> Changes in v2:
> * Add T-b
> * None
> ---
>  drivers/mtd/nand/raw/cafe_nand.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/cafe_nand.c b/drivers/mtd/nand/raw/cafe_nand.c
> index f7e537836d55..36685bee9d83 100644
> --- a/drivers/mtd/nand/raw/cafe_nand.c
> +++ b/drivers/mtd/nand/raw/cafe_nand.c
> @@ -470,6 +470,7 @@ static int cafe_nand_read_page(struct nand_chip *chip, uint8_t *buf,
>  {
>  	struct mtd_info *mtd = nand_to_mtd(chip);
>  	struct cafe_priv *cafe = nand_get_controller_data(chip);
> +	void *pagebuf = nand_get_data_buf(chip);
>  	unsigned int max_bitflips = 0;
>  	u32 ecc_result, status;
>  
> @@ -477,8 +478,11 @@ static int cafe_nand_read_page(struct nand_chip *chip, uint8_t *buf,
>  		cafe_readl(cafe, NAND_ECC_RESULT),
>  		cafe_readl(cafe, NAND_ECC_SYN_REG(0)));
>  
> -	nand_read_page_op(chip, page, 0, buf, mtd->writesize);
> -	chip->legacy.read_buf(chip, chip->oob_poi, mtd->oobsize);
> +	nand_read_page_op(chip, page, 0, pagebuf,
> +			  mtd->writesize + mtd->oobsize);

Shouldn't accesses to the OOB area be under conditions like if
(oob_required)? Unless of course reading the OOB like this is mandatory
in order to get the ECC engine working - I did not check.

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