--- In "jan_fristedt" <> wrote:
>
> Hi all,
> I'm new to using ARM9 with Linux and have two questions:
>
> 1. Is it possible to use DMA in user mode (without writing a driver)?
> 2. Is it possible to use interrupts in user mode (without writing a
> driver)?
>
> I have a feeling it's not...
> /Janne
>
The biggest problem with using the DMA controller in userspace is you
need to know how to translate virtual address' to physical address.
You would want to make sure you mlock() any user memory before using it
for DMA.
Another problem is if you want to set up an IRQ handler. DMA can be
used without IRQs though.
To use DMA mostly from userspace would probably require a stub kernel
driver that could do the above 2 (or one-- if you didn't need IRQs)
things for you.
The TS "bootload" Linux bootloader program makes use of a simple driver
that allows the bootload userspace program to figure out physical
addresses for the userspace buffers.
//Jesse Off
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