On Wed, 30 Mar 2016 09:51:43 -0700
Mark Brown [off-list ref] wrote:

On Wed, Mar 30, 2016 at 05:39:51PM +0200, Boris Brezillon wrote:

quoted

sg_alloc_table_from_buf() provides an easy solution to create an sg_table
from a virtual address pointer. This function takes care of dealing with
vmallocated buffers, buffer alignment, or DMA engine limitations (maximum
DMA transfer size).

This seems nice.  Should we also have a further helper on top of this
which will get constraints from a dmaengine, it seems like it'd be a
common need?

Yep, we could create a wrapper extracting dma_slave caps info,
converting it to sg_constraints and calling sg_alloc_table_from_buf().
But let's try to get this function accepted first, and I'll send another
patch providing this wrapper.

BTW, do you see other things that should be added in sg_constraints?

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com