dma_alloc_coherent versus streaming DMA, neither works satisfactory

[Daniel Drake]

On Thu, May 7, 2015 at 5:18 AM, Mike Looijmans <mike.looijmans at topic.nl> wrote:
> I reverted all my patches and workarounds. Indeed, the kernel needs a
> "coherent" version of the dma_mmap routine, as the current version will map
> it as non-cachable, resulting in a big performance hit (and nullifying the
> whole idea behind it).
>
> I'll test it further on my 'hardware' and cook up a patch that correctly
> maps the coherent pages.

Sorry that I have only read this thread briefly, but I wonder if this
is what you are looking for:
http://lists.infradead.org/pipermail/linux-arm-kernel/2015-February/325489.html

Thanks
Daniel