[U-Boot] [PATCH 1/2] arm: omap: nand: introduce CONFIG_NAND_OMAP_SW_ECC_LEGACY

Nikita Kiryanov nikita at compulab.co.il
Thu Dec 12 12:50:47 CET 2013


On 12/11/2013 11:18 PM, Gupta, Pekon wrote:
> Hi Nikita,
>
>> From: Nikita Kiryanov [mailto:nikita at compulab.co.il]
>> Commit "mtd: nand: omap: enable BCH ECC scheme using ELM for generic platform"
>> (d016dc42cedbf6102e100fa9ecb58462edfb14f8) changed the way software ECC is
>> configured, both during boot, and during ecc switch, in a way that is not
>> backwards compatible with older systems (for example, X-Loader on CM-T35 relies
>> on the old behavior).
>>
>> The culprit is the line which assigns ecc.size for software ECC.
>> Older version of omap_gpmc.c always assigned ecc.size = 0 when configuring for
>> software ecc, relying on nand_scan_tail() to select a default for ecc.size
>> (256), while the new version of omap_gpmc.c assigns ecc.size = pagesize, which
>> is likely to not be 256.
>>
> Then its just one-line change.. Remove "ecc.size = pagesize".
> Why do you need to add a newer config for that ?
> This ecc-scheme (HAM1_SW) is anyways only kept for backward compatibility
> with legacy devices. (As also mentioned in doc/README.nand)
> -----------------------------
>    CONFIG_NAND_OMAP_ECCSCHEME
> 	On OMAP platforms, this CONFIG specifies NAND ECC scheme.
> 	It can take following values:
> 	OMAP_ECC_HAM1_CODE_SW
> 		1-bit Hamming code using software lib.
> 		(for legacy devices only)
> -----------------------------

OK if that's the case then that makes things easier. New patch coming
up.

-- 
Regards,
Nikita.


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