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] 28c015a9daab ("mtd: davinci-nand: disable subpage write for keystone-nand") Fixes: 6a4123e581b3 ("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>