cfi_cmdset_0001 get_chip()put_chip() contender/loaner, what does it do?

[Joakim Tjernlund]

On Tue, 2007-06-12 at 10:50 -0400, Nicolas Pitre wrote:
> On Tue, 12 Jun 2007, Joakim Tjernlund wrote:
> 
> > In the beginning of get_chip() and put_chip for the cfi_cmdset_0001
> > driver there is this "fight" over access to the chip that I don't
> > understand. Why is it there and why don't the other drivers need it?
> 
> It is there to support the Intel Sibley NOR flash chips which have the 
> ability to allow read operations in many part of the chip at the same 
> time as an erase or a write operation taking place in another part of 
> the chip.  The erase and write operation, though, cannot have more than 
> one instance on the whole chip.
> 
> To facilitate the driver implementation, the Sibley flash is subdivided 
> in many "chips" corresponding to those parts mentioned above.  However, 
> since the ability to write is shared amongst all those "chips" then it 
> sometimes must be obtained from another chip.  The other chip might 
> concede it or it might not.  That's the "fighting".

I see, the reason for me asking about this is that I am seeing some
very long stalls, see the "JFFS2 appears to "freeze" during erase,
version 2" thread and I am starting to suspect the above mentioned code,
mostly because I don't understand this code and don't know where else
to look. Do you see anything that could explain what I am seeing?

 Jocke