[ECOS] NAND for STM32, YAFFS and UFFS

[Simon Kallweit <simon.kallweit@intefo.ch>]

Hello

I added NAND support for the STM3210E-EVAL board today. I currently use 
Ross's framework as I think it's a bit more lightweight than Rutgers, 
which is rather important for me at the moment. The port consists of the 
HAL part as well as a new ST NANDxxxx3A NAND driver. Both were started 
as copies of Ross's code. What is still missing is interrupt mode and 
the usage of STM32's onboard ECC computation unit.

I wanted to do some quick tests with YAFFS, as my initial port of the 
UFFS filesystem is not yet done, and I wanted to get some rough numbers 
of what resources are needed to run YAFFS. Unfortunately it turned out 
that the YAFFS port does not handle small page NANDs, as one is found on 
the STM32 evalboard. Further investigation showed that YAFFS1 was using 
small page NANDs and YAFFS2 is used on 1k++ page NANDs. The eCos port is 
based on YAFFS2 I guess, so I think this should be renamed properly. Or 
was there a plan to support both YAFFS1 and YAFFS2?

After some first investigation of the UFFS source code it seems that it 
needs quite a bit of work to make it work properly with eCos and not 
have hacks all over the place. But it seems that YAFFS does still use 
too much resources for our usage, so I think I need to work on a simpler 
one and UFFS still looks like a good start ...

Simon

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