This fixes subpage writes when using 4-bit HW ECC.
There has been numerous reports about ECC errors with devices using this
driver for a while. Also the 4-bit ECC has been reported as broken with
subpages in [1] and with 16 bits NANDs in the driver and in mach* board
files both in mainline and in the vendor BSPs.
What I saw with 4-bit ECC on a 16bits NAND (on an LCDK) which got me to
try reinitializing the ECC engine:
- R/W on whole pages properly generates/checks RS code
- try writing the 1st subpage only of a blank page, the subpage is well
written and the RS code properly generated, re-reading the same page
the HW detects some ECC error, reading the same page again no ECC
error is detected
Note that the ECC engine is already reinitialized in the 1-bit case.
Tested on my LCDK with UBI+UBIFS using subpages.
This could potentially get rid of the issue workarounded in [1].
[1] 28c015a9da ("mtd: davinci-nand: disable subpage write for keystone-nand")
Fixes: 6a4123e581 ("mtd: nand: davinci_nand, 4-bit ECC for smallpage")
Cc: <stable@vger.kernel.org>
Signed-off-by: Karl Beldan <kbeldan@baylibre.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
f6d7c1b559