On Tuesday 06 January 2009, Griffis, Brad wrote:
> > > The more descriptive terms are active/reload.  The "active"
> > > set is the one that the EDMA actually uses for transferring
> > > data.  When the transfer is completed, if the active channel
> > > specifies a "link" set (i.e. the reload set), then that set
> > > will be copied over the "active" set.
> > 
> > Agreed on reload.  (Slavery is bad!)
> > 
> > Not about "active" though.  For one thing, they won't
> > always be active ... they need to be triggered first
> > (by hardware event, software, or chaining).
> > 
> > How to present this is a bit of a puzzle.  ...
> 
> Hmmm, yes, I see what you mean about "active".  I didn't mean
> "active" as in "currently transferring", but that would be
> how most people would interpret the term in isolation.     
> 
> I think a more appropriate term would be the "mapped"
> PSET, because each channel is mapped to a corresponding
> PSET.  So when a transfer is initiated for a given channel
> the corresponding/mapped PSET is utilized and updated.

Or perhaps "bound", since most current EDMAs don't support
mapping except in the trivial "one-to-one" sense.

That still doesn't strike me as the best choice.  The
EDMA docs talk explicitly about channels and PaRAM; it'd
likely be better to follow that lead, instead of trying
to come up with new terminology just for the Linux API.
That is, pretty much use the terminology you used in your
first post on this thread, instead of what's been used by
this API since it was created ...

After Kevin gets back and merges most of the patches that
have been submitted (or NAKs them for whatever reason),
it'll be time to think about fixing this deeper goofage.


> OMAP35xx has both System DMA (SDMA) and EDMA.  The EDMA
> is part of the IVA2.2 module.

And thus isn't available to Linux, so we don't need to
worry about providing a Linux API for it.  Your DSP
focus is showing again, Brad!  :)

- Dave


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