Dec. 5, 2015
1:12 a.m.
On Thu, Dec 3, 2015 at 1:29 PM, Random Guy <random.guy.from.russia@gmail.com> wrote:
I have a device with a piece of RAM. That memory is accessible to CPU. I write a driver for that device and it maps device memory directly to userspace processes. This mapping is cacheable. So far so good.
Ok, I did some research and all drivers that I've found that map memory to userspace do it with caching disabled. After some more reading, especially http://events.linuxfoundation.org/sites/events/files/slides/20140429-dma.pdf I conclude that cacheable mapping of device memory to userspace is not supported in linux at all. Is that correct? TIA