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Re: RE: AT91 patches
- From: Jonathan Larmour <jifl at eCosCentric dot com>
- To: Doug Fraser <dfraser at photuris dot com>
- Cc: "ecos-discuss (E-Mail)" <ecos-discuss at sources dot redhat dot com>
- Date: Thu, 30 Jan 2003 16:17:46 +0000
- Subject: Re: [ECOS] RE: AT91 patches
- References: <E2D27064CD59574F88D05AEF5728396D015900C8@PH01SRV02.photuris.com>
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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