[U-Boot] am33xx : bit-flip correction in oob

[Gupta, Pekon]

Fixed some copy paste typos in ECC layout below..

>From: Gupta, Pekon
>Hello Marek,
>
>>From: Belisko Marek [mailto:marek.belisko at gmail.com]
>>
>>CC-ing Pekon Gupta which add those changes in commit:
>>6e562b1106ea6afc78752f50925e87e9dd14f8b4
>>
>>On Tue, Apr 15, 2014 at 12:47 PM, Belisko Marek <marek.belisko at gmail.com> wrote:
>>> Hi,
>>>
>>> we're running 2014.04-rc3 on custom am335x board (same configuration as BBB).
>>> When spl is loading u-boot from nand flash we can see a lot of
>>> messages in console:
>>> nand: bit-flip corrected @oob=0
>>>
>>> It is always the same position (seems to be first byte in oob).
>>> Anybody experienced same problem?
>>> I've tested on 2 different flashes and result is same.
>>>
>>I was able to track down that read ecc from gpmc return always first
>>byte as 0xFF (in omap_calculate_ecc())
>
>This shouldn't be the case if the page is programmed.
>Following is the expected ECC layout of BCH8
>OOB[0]:   Bad block marker
>OOB[1]:   Bad block marker
>OOB[2]:   ecc_sector0_byte[0] = read_ecc[0]   <---
>OOB[3]:   ecc_sector0_byte[1]
>OOB[4]:   ecc_sector0_byte[2]
>OOB[5]:   ecc_sector0_byte[3]
>OOB[6]:   ecc_sector0_byte[4]
>OOB[7]:   ecc_sector0_byte[5]
>OOB[8]:   ecc_sector0_byte[6]
>OOB[9]:   ecc_sector0_byte[7]
>OOB[10]:   ecc_sector0_byte[8]
>OOB[11]:   ecc_sector0_byte[9]
>OOB[12]:   ecc_sector0_byte[10]
>OOB[13]:   ecc_sector0_byte[11]
>OOB[14]:   ecc_sector0_byte[12]
>OOB[15]:   reserved (0x00)   = read_ecc[13] <---
>OOB[16]:   ecc_sector1_byte[0]
>OOB[17]:   ecc_sector1_byte[1]
>OOB[18]:   ecc_sector2_byte[2]
>OOB[19]:   ecc_sector3_byte[3]
>....
>
>
>>and thus function omap_correct_data_bch() always trying to repair
>>bit-flips in first oob byte. Can this be caused by
>>flash? Any pointers?
>>
>>> In config we're using:
>>> #define CONFIG_NAND_OMAP_ECCSCHEME      OMAP_ECC_BCH8_CODE_HW
>>> #define CONFIG_NAND_OMAP_ELM
>>>
>Something seems to be wrong elsewhere.
>(1) please use 'nand dump' to check above layout
>
>(2) Also please send me your device datasheet
>
>(3) If you using x16 device, then you might need to pull-in following patch series..
>http://lists.denx.de/pipermail/u-boot/2014-April/176834.html
>
>OR
>Use below hack, just for testing (only for x16 devices)..
>-----------------------
>diff --git a/arch/arm/cpu/armv7/am33xx/mem.c b/arch/arm/cpu/armv7/am33xx/mem.c
>index 56c9e7d..b166a94 100644
>--- a/arch/arm/cpu/armv7/am33xx/mem.c
>+++ b/arch/arm/cpu/armv7/am33xx/mem.c
>@@ -64,7 +64,7 @@ void gpmc_init(void)
>        u32 base = CONFIG_SYS_FLASH_BASE;
> #elif defined(CONFIG_NAND)
> /* configure GPMC for NAND */
>-       const u32  gpmc_regs[GPMC_MAX_REG] = {  M_NAND_GPMC_CONFIG1,
>+       const u32  gpmc_regs[GPMC_MAX_REG] = {  M_NAND_GPMC_CONFIG1 | 0x1000,
>                                                M_NAND_GPMC_CONFIG2,
>                                                M_NAND_GPMC_CONFIG3,
>                                                M_NAND_GPMC_CONFIG4,
>-----------------------


with regards, pekon