Hello,

On Monday, June 20, 2011 4:40 PM Russell King - ARM Linux wrote:

On Mon, Jun 20, 2011 at 09:50:09AM +0200, Marek Szyprowski wrote:

quoted

This patch converts all dma_sg methods to be generic (independent of the
current DMA mapping implementation for ARM architecture). All dma sg
operations are now implemented on top of respective
dma_map_page/dma_sync_single_for* operations from dma_map_ops structure.

No.  We really don't want to do this.

I assume you want to keep the current design for performance reasons?

It's really not a problem for me. I can change my patches to keep 
arm_dma_*_sg_* functions and create some stubs for dmabounce version.

If we want to move the dsb() out of the mapping functions (which I
have a patch for) to avoid doing a dsb() on each and every sg segment,
then we must not use the generic stuff.

Ok, specialized (optimized) version of dma_*_sg_* operations are definitely
better. The current version just calls respective dma_single_* operations in
a loop, so in my patches I decided to create some generic version just to
simplify the code. 

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center