Re: [PATCH] mtd: nand: gpmi: Fix subpage reads

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Tue, 23 Jan 2018 11:13:17 +0100
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> Commit 25f815f66a14 ("mtd: nand: force drivers to explicitly send
> READ/PROG commands") added a call to nand_read_page_op() in
> gpmi_ecc_read_page(), which means this function now sends a READ0
> command and place the data pointer at the beginning of the page. This
> logic is breaking gpmi_ecc_read_subpage() which was calling
> gpmi_ecc_read_page() and expected it to only retrieve the data without
> sending the READ0 command.
> 
> Create a gpmi_ecc_read_page_data() helper which only does the data
> retrieval and ECC correction steps and implement gpmi_ecc_read_page()
> as a wrapper that calls nand_read_page_op()+gpmi_ecc_read_page_data().
> 
> This way, gpmi_ecc_read_subpage() can call gpmi_ecc_read_page_data()
> which restores the logic we had before commit 25f815f66a14 ("mtd: nand:
> force drivers to explicitly send READ/PROG commands").
> 

Applied.

> Fixes: 25f815f66a14 ("mtd: nand: force drivers to explicitly send READ/PROG commands")
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> ---
>  drivers/mtd/nand/gpmi-nand/gpmi-nand.c | 18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> index 3198f5f79a82..93f212457d4d 100644
> --- a/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> +++ b/drivers/mtd/nand/gpmi-nand/gpmi-nand.c
> @@ -1029,11 +1029,13 @@ static void block_mark_swapping(struct gpmi_nand_data *this,
>  	p[1] = (p[1] & mask) | (from_oob >> (8 - bit));
>  }
>  
> -static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
> -				uint8_t *buf, int oob_required, int page)
> +static int gpmi_ecc_read_page_data(struct nand_chip *chip,
> +				   uint8_t *buf, int oob_required,
> +				   int page)
>  {
>  	struct gpmi_nand_data *this = nand_get_controller_data(chip);
>  	struct bch_geometry *nfc_geo = &this->bch_geometry;
> +	struct mtd_info *mtd = nand_to_mtd(chip);
>  	void          *payload_virt;
>  	dma_addr_t    payload_phys;
>  	void          *auxiliary_virt;
> @@ -1043,8 +1045,6 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
>  	unsigned int  max_bitflips = 0;
>  	int           ret;
>  
> -	nand_read_page_op(chip, page, 0, NULL, 0);
> -
>  	dev_dbg(this->dev, "page number is : %d\n", page);
>  	ret = read_page_prepare(this, buf, nfc_geo->payload_size,
>  					this->payload_virt, this->payload_phys,
> @@ -1178,6 +1178,14 @@ static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
>  	return max_bitflips;
>  }
>  
> +static int gpmi_ecc_read_page(struct mtd_info *mtd, struct nand_chip *chip,
> +			      uint8_t *buf, int oob_required, int page)
> +{
> +	nand_read_page_op(chip, page, 0, NULL, 0);
> +
> +	return gpmi_ecc_read_page_data(chip, buf, oob_required, page);
> +}
> +
>  /* Fake a virtual small page for the subpage read */
>  static int gpmi_ecc_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
>  			uint32_t offs, uint32_t len, uint8_t *buf, int page)
> @@ -1257,7 +1265,7 @@ static int gpmi_ecc_read_subpage(struct mtd_info *mtd, struct nand_chip *chip,
>  
>  	/* Read the subpage now */
>  	this->swap_block_mark = false;
> -	max_bitflips = gpmi_ecc_read_page(mtd, chip, buf, 0, page);
> +	max_bitflips = gpmi_ecc_read_page_data(chip, buf, 0, page);
>  
>  	/* Restore */
>  	writel(r1_old, bch_regs + HW_BCH_FLASH0LAYOUT0);