u-boot/drivers/mtd
Miquel Raynal c907464a0a mtd: rawnand: pxa3xx: fix 2kiB pages with 8b strength chips layout
The initial layout for such NAND chips was the following:

+----------------------------------------------------------------------------+
| 1024 (data) | 30 (ECC) | 1024 (data) | 30 (ECC) | 32 (free OOB) | 30 (ECC) |
+----------------------------------------------------------------------------+

This layout has a weakness: reading empty pages trigger ECC errors
(this is expected), but the hardware ECC engine tries to correct the
data anyway and creates itself bitflips, hence bitflips are detected
in erased pages while actually there are none in the NAND chip.

Two solutions have been found at the same time. One was to enlarge the
free OOB area to 64 bytes, changing the layout to be:

+----------------------------------------------------------------------------+
| 1024 (data) | 30 (ECC) | 1024 (data) | 30 (ECC) | 64 (free OOB) | 30 (ECC) |
+----------------------------------------------------------------------------+
                                                    ^^

The very big drawbacks of this solution are:
1/ It prevents booting from NAND.
2/ The current Linux driver (marvell_nand) does not have such problem
because it already re-reads possible empty pages in raw mode before
checking for bitflips. Using different layouts in U-Boot and Linux
would simply not work.

As this driver does support raw reads now and uses it to check for
empty pages, let's forget about this broken hack and return to the
initial layout with only 32 free OOB bytes.

Fixes: ac56a3b30c ("mtd: nand: pxa3xx: add support for 2KB 8-bit flash")
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jagan Teki <jagan@openedev.com>
2018-11-22 11:38:13 +05:30
..
nand mtd: rawnand: pxa3xx: fix 2kiB pages with 8b strength chips layout 2018-11-22 11:38:13 +05:30
onenand mtd: Fallback to ->_read/write_oob() when ->_read/write() is missing 2018-09-20 20:10:49 +05:30
spi Merge branch 'master' of git://git.denx.de/u-boot-spi 2018-10-12 11:54:13 -04:00
ubi lib: Add hexdump 2018-06-13 07:49:12 -04:00
ubispl SPDX: Convert all of our multiple license tags to Linux Kernel style 2018-05-07 10:24:31 -04:00
altera_qspi.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
cfi_flash.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
cfi_mtd.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
jedec_flash.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
Kconfig mtd: Drop duplicate MTD_PARTITIONS Kconfig option 2018-11-13 18:53:10 +05:30
Makefile cmd: mtd: add 'mtd' command 2018-10-02 22:12:32 +05:30
mtd-uclass.c mtd: uclass: add probe function 2018-10-02 22:12:31 +05:30
mtd_uboot.c mtd: Use default mtdparts/mtids when not defined in the environment 2018-11-13 18:53:10 +05:30
mtdconcat.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
mtdcore.c mtd: mtdpart: implement proper partition handling 2018-10-02 22:12:32 +05:30
mtdcore.h mtd: move definitions to enlarge their range 2018-09-20 20:10:49 +05:30
mtdpart.c mtd: mtdpart: implement proper partition handling 2018-10-02 22:12:32 +05:30
mw_eeprom.c
pic32_flash.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
renesas_rpc_hf.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
st_smi.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
stm32_flash.c SPDX: Convert all of our single license tags to Linux Kernel style 2018-05-07 09:34:12 -04:00
stm32_flash.h stm32: stm32f4: move flash driver to mtd driver location 2016-03-26 18:49:28 -04:00