Re: [PATCH] nand: sunxi: fix write to USER_DATA reg

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

Hi Brian,

On Thu, 30 Jul 2015 12:01:06 +0200
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:

> The USER_DATA register cannot be accessed using byte accessors on A13
> SoCs, thus triggering a bug when using memcpy_toio on this register.
> Declare a temporary u32 variable to store the USER_DATA value and access
> the register with writel.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Could you consider taking this patch for 4.3 (if it's too late for
4.3-rc1, could you queue it for -rc2)?

BTW, I'd like to add

Cc: <stable@vger.kernel.org> # 3.19+

should I resend a new version or could you add it while you're applying
the patch on your branch?

Thanks,

Boris

> ---
>  drivers/mtd/nand/sunxi_nand.c | 24 +++++++++++++-----------
>  1 file changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/mtd/nand/sunxi_nand.c b/drivers/mtd/nand/sunxi_nand.c
> index 6f93b29..5e374ab 100644
> --- a/drivers/mtd/nand/sunxi_nand.c
> +++ b/drivers/mtd/nand/sunxi_nand.c
> @@ -624,6 +624,8 @@ static int sunxi_nfc_hw_ecc_write_page(struct mtd_info *mtd,
>  	writel(tmp, nfc->regs + NFC_REG_ECC_CTL);
>  
>  	for (i = 0; i < ecc->steps; i++) {
> +		u32 user_data;
> +
>  		if (i)
>  			chip->cmdfunc(mtd, NAND_CMD_RNDIN, i * ecc->size, -1);
>  
> @@ -632,16 +634,16 @@ static int sunxi_nfc_hw_ecc_write_page(struct mtd_info *mtd,
>  		offset = layout->eccpos[i * ecc->bytes] - 4 + mtd->writesize;
>  
>  		/* Fill OOB data in */
> -		if (oob_required) {
> -			tmp = 0xffffffff;
> -			memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE, &tmp,
> -				    4);
> +		if (!oob_required) {
> +			user_data = 0xffffffff;
>  		} else {
> -			memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE,
> -				    chip->oob_poi + offset - mtd->writesize,
> -				    4);
> +			memcpy(&user_data,
> +			       chip->oob_poi + layout->oobfree[i].offset, 4);
> +			user_data = le32_to_cpu(user_data);
>  		}
>  
> +		writel(user_data, nfc->regs + NFC_REG_USER_DATA_BASE);
> +
>  		chip->cmdfunc(mtd, NAND_CMD_RNDIN, offset, -1);
>  
>  		ret = sunxi_nfc_wait_cmd_fifo_empty(nfc);
> @@ -772,13 +774,13 @@ static int sunxi_nfc_hw_syndrome_ecc_write_page(struct mtd_info *mtd,
>  		/* Fill OOB data in */
>  		if (oob_required) {
>  			tmp = 0xffffffff;
> -			memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE, &tmp,
> -				    4);
>  		} else {
> -			memcpy_toio(nfc->regs + NFC_REG_USER_DATA_BASE, oob,
> -				    4);
> +			memcpy(&tmp, oob, sizeof(tmp));
> +			tmp = le32_to_cpu(tmp);
>  		}
>  
> +		writel(tmp, nfc->regs + NFC_REG_USER_DATA_BASE);
> +
>  		tmp = NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD | NFC_ACCESS_DIR |
>  		      (1 << 30);
>  		writel(tmp, nfc->regs + NFC_REG_CMD);



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com