On Wed, Jan 15, 2014 at 11:45 PM, m silverstri <michael.j.silverstri@xxxxxxxxx> wrote:
Hi,
If my application allocate memory for input and output buffers, and
pass the pointer to a kernel driver (via v4l2 queue buffer operation),
can the kernel driver access it? Do I need to setup DMA before teh
kernel driver can read/write to it?
You can transfer data to & from kernelspace/userspace by using copy_to/from_user() API.
However, for DMA I think you might also want to lock the user pages in memory so that they are not invalidated when the owning process is scheduled out. This is a very high-level gist, but there a lot of resources out there which show how this can be done.
HTH,
-mandeep
Thank you.
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