Re: [PATCH] mtd: nand: davinci: add comment on NAND subpage write status on keystone

From: Boris Brezillon
Date: Tue Apr 11 2017 - 07:39:01 EST


On Thu, 30 Mar 2017 20:09:30 +0530
Sekhar Nori <nsekhar@xxxxxx> wrote:

> Add a comment clarifying that NAND subpage write on keystone works,
> but is not being enabled in the interest of backward compatibility.

Applied.

Thanks,

Boris

>
> Signed-off-by: Sekhar Nori <nsekhar@xxxxxx>
> ---
> drivers/mtd/nand/davinci_nand.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/mtd/nand/davinci_nand.c b/drivers/mtd/nand/davinci_nand.c
> index 27fa8b87cd5f..531c51991e57 100644
> --- a/drivers/mtd/nand/davinci_nand.c
> +++ b/drivers/mtd/nand/davinci_nand.c
> @@ -581,6 +581,17 @@ static struct davinci_nand_pdata
> "ti,davinci-nand-use-bbt"))
> pdata->bbt_options = NAND_BBT_USE_FLASH;
>
> + /*
> + * Since kernel v4.8, this driver has been fixed to enable
> + * use of 4-bit hardware ECC with subpages and verified on
> + * TI's keystone EVMs (K2L, K2HK and K2E).
> + * However, in the interest of not breaking systems using
> + * existing UBI partitions, sub-page writes are not being
> + * (re)enabled. If you want to use subpage writes on Keystone
> + * platforms (i.e. do not have any existing UBI partitions),
> + * then use "ti,davinci-nand" as the compatible in your
> + * device-tree file.
> + */
> if (of_device_is_compatible(pdev->dev.of_node,
> "ti,keystone-nand")) {
> pdata->options |= NAND_NO_SUBPAGE_WRITE;