[PATCH 1/3] dmaengine: add dma_get_slave_sg_limits()

Vinod Koul vinod.koul at intel.com
Mon Jul 29 02:44:15 EDT 2013


On Thu, Jul 18, 2013 at 01:57:33PM -0500, Joel Fernandes wrote:
> On 07/18/2013 12:08 PM, Russell King - ARM Linux wrote:
> > As for the maximum number of scatterlist entries, really that's a bug in
> > the DMA engine implementations if they can't accept arbitary lengths.
> > I've created DMA engine drivers for implementations where you have to
> > program each segment individually, ones which can have the current and
> > next segments, as well as those which can walk a list.  Provided you get
> > informed of a transfer being completed, there really is no reason for a
> > DMA engine driver to limit the number of scatterlist entries that it
> > will accept.
> 
> Sure, that makes sense. Can you point to such a typical example
> implementation to get some ideas?
MXS MMC driver uses this: drivers/mmc/host/mxs-mmc.c
And dma engine driver for this is mxs-dma.c

~Vinod
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