Messages in this thread | | | Date | Sun, 21 Jun 2020 22:36:34 +0200 | From | Federico Vaga <> | Subject | Re: DMA Engine: Transfer From Userspace |
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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)
>Federico, what use case do you have in mind?
Userspace drivers
>We should keep in mind dmaengine is an in-kernel interface providing >services to various subsystems, so you go thru the respective subsystem >kernel interface (network, display, spi, audio etc..) which would in >turn use dmaengine. > >-- >~Vinod
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