android_kernel_oneplus_msm8998/drivers/mtd
Karl Beldan 05d721d61e mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl
commit f6d7c1b5598b6407c3f1da795dd54acf99c1990c upstream.

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")
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-07 15:23:40 +02:00
..
chips
devices
lpddr
maps mtd: pmcmsp-flash: Allocating too much in init_msp_flash() 2016-09-30 10:18:37 +02:00
nand mtd: nand: davinci: Reinitialize the HW ECC engine in 4bit hwctl 2016-10-07 15:23:40 +02:00
onenand
spi-nor mtd: spi-nor: remove micron_quad_enable() 2016-05-04 14:48:52 -07:00
tests
ubi ubi: Fix race condition between ubi device creation and udev 2016-08-20 18:09:26 +02:00
afs.c
ar7part.c
bcm47xxpart.c
bcm63xxpart.c
cmdlinepart.c
ftl.c
inftlcore.c
inftlmount.c
Kconfig
Makefile
mtd_blkdevs.c
mtdblock.c
mtdblock_ro.c
mtdchar.c
mtdconcat.c
mtdcore.c
mtdcore.h
mtdoops.c
mtdpart.c
mtdsuper.c
mtdswap.c
nftlcore.c
nftlmount.c
ofpart.c
redboot.c
rfd_ftl.c
sm_ftl.c
sm_ftl.h
ssfdc.c