On Fri, Sep 21, 2012 at 07:47:21PM +0100, Russell King wrote:

On Fri, Sep 21, 2012 at 10:45:29PM +0530, S, Venkatraman wrote:

quoted

On Thu, Sep 20, 2012 at 8:13 PM, Matt Porter [off-list ref] wrote:

quoted

The EDMA DMAC has a hardware limitation that prevents supporting
scatter gather lists with any number of segments. Since the EDMA
DMA Engine driver sets the maximum segments to 16, we do the
same.

Note: this can be removed once the DMA Engine API supports an
API to query the DMAC's segment limitations.

I wouldn't want to bind the properties of EDMA to omap_hsmmc as this patch
suggests. Why don't we have a max_segs property, which when explicitly specified
in DT, will override the default ?

Why not have a generic way that DMA engine can export these kinds of
properties?

That's exactly what my note above is suggesting...

Something along the lines of:

	struct slave_sg_caps
	{
		int max_segs;	/* <0 is no limit */
	}

	struct slave_sg_cap *
	dmaengine_get_slave_sg_caps(struct dma_chan *chan);

I'm sure there are or will be other characteristics worth providing to
slave drivers.

-Matt

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