Messages in this thread | | | Date | Mon, 22 Jun 2020 08:57:27 +0200 | From | Federico Vaga <> | Subject | Re: DMA Engine: Transfer From Userspace |
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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
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