On Mon, Jun 22, 2020 at 10:17:33AM +0530, Vinod Koul wrote:
On 21-06-20, 22:36, Federico Vaga wrote:
On Sun, Jun 21, 2020 at 12:54:57PM +0530, Vinod Koul wrote:
> On 19-06-20, 16:31, Dave Jiang wrote:
> >
> >
> > On 6/19/2020 3:47 PM, Federico Vaga wrote:
> > > Hello,
> > >
> > > is there the possibility of using a DMA engine channel from userspace?
> > >
> > > Something like:
> > > - configure DMA using ioctl() (or whatever configuration mechanism)
> > > - read() or write() to trigger the transfer
> > >
> >
> > I may have supposedly promised Vinod to look into possibly providing
> > something like this in the future. But I have not gotten around to do that
> > yet. Currently, no such support.
>
> And I do still have serious reservations about this topic :) Opening up
> userspace access to DMA does not sound very great from security point of
> view.
I was thinking about a dedicated module, and not something that the DMA engine
offers directly. You load the module only if you need it (like the test module)
But loading that module would expose dma to userspace.
Of course, but users *should* know what they are doing ... right? ^_^'
> Federico, what use case do you have in mind?
Userspace drivers
more the reason not do do so, why cant a kernel driver be added for your
usage?
Yes of course, I was just wandering if there was a kernel API.
--
~Vinod
