[ECOS] NAND Flash support in eCos?

[Gary Thomas]

Please keep your replies on the list so that all may benefit.

Jim Seymour wrote:
> Gary Thomas wrote:
>> Jim Seymour wrote:
>>> I found a few discussions back in 2004 regarding eCos support for 
>>> NAND Flash, but can't find anything more recent.
>>>
>>> Has anybody implemented a flash driver for any NAND Flash chips? 
>>> (Specifically, the Samsung K9F1208U0B)  Our platform will be an Atmel 
>>> ARM9 (AT91SAM9260), if that matters.
>>>
>>> Related to this: Does anybody know of any easy-to-use error detection 
>>> and correction code?  I don't think I'll need a full file system, but 
>>> I'll need to at least have a simple lookup table in order to map 
>>> around bad blocks.
>>>
>>
>> NAND FLASH (RedBoot only, minimal drivers) is supported on the TAMS MOAB
>> using Toshiba chips.  Just look in the repository...
> 
> Thank you.  This looks like a real good starting point for me.
> 
> I'm curious, though.  The Toshiba drivers seem to assume the flash is in 
> code space - although NAND flash (as I understand it) cannot be used to 
> directly execute code.  Is this a legacy from the NOR flash driver it 
> was based on?  Or is there some eCos weirdness that I need to be aware of?
> 

NAND FLASH is treated differently - it cannot be accessed
directly and the 'flash_read_buf()' function is used to stage
a portion of the FLASH into RAM.  The extant drivers do
not attempt to remap any bad sectors - simple bit error
discovery/repair using ECC only.

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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