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Subject: Re: Driver for tightly coupled memory
From: Ben Nizette <bn@niasdigital.com>
To: Alessio Sangalli <alesan@manoweb.com>
Cc: Ben Dooks <ben-linux@fluff.org>,
       linux-kernel <linux-kernel@vger.kernel.org>
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	 <20080916093513.GF1916@fluff.org.uk>  <48CFEF3F.5040901@manoweb.com>
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Organization: Nias Digital
Date: Wed, 17 Sep 2008 08:27:02 +1000
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On Tue, 2008-09-16 at 10:39 -0700, Alessio Sangalli wrote:
> Ben Dooks wrote:
> > IIRC, there's no current support for using TCMs.
> 
> I think I will write a module that implements a software FIFO. One
> function to allocate a FIFO n words deep, a "push" and a "pop" and
> similar. The calling module will have to setup the FIFO and use it
> probably in ISRs or similar (the policy will totally remain in the
> caller module). Any comments on such approach?

I'd feel uncomfortable about picking an arbitrary function for the TCM
to accomplish.  Why don't you just set up a genalloc on that RAM and let
the user use it for what they will?

If a driver needs a quick FIFO it can attempt to get the RAM for said
FIFO from the genalloc and fall back to main memory otherwise.  Simple,
flexible, easy :-)

	--Ben.