[PATCH v7] mtd: gpmi: Deal with bitflips in erased regions

[Huang Shijie]

On Fri, Jan 03, 2014 at 10:27:19PM +0100, Elie De Brauwer wrote:
> The BCH block typically used with a GPMI block on an i.MX28/i.MX6 is only
> able to correct bitflips on data actually streamed through the block.
> When erasing a block the data does not stream through the BCH block
> and therefore no ECC data is written to the NAND chip. This causes
> gpmi_ecc_read_page to return failure as soon as a single non-1-bit is
> found in an erased page. Typically causing problems at higher levels
> (ubifs corrupted empty space warnings). This problem was also observed
> when using SLC NAND devices.
> 
> This patch configures the BCH block to mark a block as 'erased' if
> not too much bitflips are found (by setting the erase threshold). A
> consequence of this is that whenever an erased page is read, the
> number of bitflips will be counted and corrected in software,
> allowing the upper layers to take proper actions.
> 
> Signed-off-by: Elie De Brauwer <eliedebrauwer at gmail.com>
> Acked-by: Peter Korsgaard <peter at korsgaard.com>
> Acked-by: Huang Shijie <b32955 at freescale.com>

I am okay with this patch.

thanks
Huang Shijie