Elan SC520 - problem with MTD

David Woodhouse dwmw2 at infradead.org
Mon Apr 23 09:10:38 EDT 2001


rob at sysgo.de said:
>  Some Background info: 
> In order to persuade the BIOS to boot from the Flash, you have to
> enable it's "disk" emulation:  the BIOS can treat each of the flash
> banks as an emulated disk. So far so good, but: these "disk" functions
> are only accessible through the BIOS int 13h call, thus, you can't
> access it from Linux.

> Worse even, the BIOS insists on doing "wear levelling" (i.e. it tries
> to distribute erases evenly over all flash blocks). It does this by
> remapping flash blocks when they have seen to many write erases.
> Therefore,  if you write a continuous stream of data to the flash
> using the BIOS int13h function, the BIOS will scatter your data all
> over the flash memory in an unpredictable way. There is no way (other
> than buying a customized BIOS from General Software) to disable his
> wear levelling. So the bottom line is: 

Has nobody tried to reverse-engineer the format they use for this and 
provide a driver in Linux? See the FTL and NFTL drivers for examples and 
ideas on how the BIOS might be doing the translation.

--
dwmw2




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