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    SubjectRe: DMA Engine: Transfer From Userspace
    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.
    >
    > > 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?

    --
    ~Vinod

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