[ECOS] RE: AT91 patches

[Jonathan Larmour]

Doug Fraser wrote:
> Agreed.
> 
> One of the drivers I used did allow the
> single FLASH array to be chopped into two sections,
> one section running in the large block mode and the
> other in small block mode, but you had to run
> two separate threads, so you had, in effect,
> two FFS running. The only difficulty was that the
> two threads had to coordinate access to the state
> machine to control erase/read/write modes.
> 
> So if the application area was running an erase in the
> large block arena, and the drivers wanted to read from
> the small block arena, you had to suspend/read/resume.
> Separate FFS, but the same chip, and the same control
> logic. Not that hard, you just have to be careful to avoid
> deadlock situations.
> 
> I am not sure (again, lack of time right now) if JFFS2
> can support the above situation. Does anybody know if
> that is supported? It is useful for things like 
> boot block flash....

JFFS2 supports multiple file system instantiations. Preventing 
simultaneous access is left to the lower layers.

Jifl
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