[PATCH] dmaengine: pl330: Set residue in tx_status callback

[Russell King - ARM Linux]

On Mon, Dec 08, 2014 at 06:37:27PM +0530, Vinod Koul wrote:
> I actually like the split model, you can also prepare txn ahead of time and
> submit them when needed.

Actually, you can't - that's not permitted.  I have email(s) from Dan
explicitly stating that it is permitted for a driver to take a spinlock
in their prepare callback, and release it when the descriptor is
submitted.  Several DMA engine drivers (particularly those in for
async_tx) do exactly that.

The reason that submit is separate from prepare is to allow DMA engine
users to set a callback - if it weren't for that, there wouldn't be a
submit step, prepare would have done everything.

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