[ECOS] NAND Flash support in eCos?

[Gary Thomas]

Jim Seymour wrote:
> Gary Thomas wrote:
>> Jim Seymour wrote:
>>> 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.  [...]
> 
> What prompted my question is the function "flash_code_overlaps" in
> .../devs/flash/toshiba/tc58xxx/current/include/flash_tc58xxx.inl
> 
> It compares the flash address with "stext" and "etext" to determine 
> whether it "overlaps currently running code".
> 
> However, since we cannot execute out of NAND flash (and, in fact, do not 
> map the NAND flash into the normal memory address space), it seems that 
> this function should always return false.
> 
> Am I misunderstanding this?  Or is it a (minor) bug?
> 

It's just a harmless bug :-)

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