title: Modify the physical address of a v4l2_buffer in kernel module
body: <p>Is it possible to modify a v4l2_buffer allocated through MMAP in userspace such that the physical address of the requested buffer points towards a desired physical memory?
  The goal is that we have a sensor writing data in a circular buffer within a reserved memory range and we would like to avoid copying the data (as they are made available by the sensor which triggers an IRQ as soon as the buffer is filled).</p>
  <p>Thank you for any help you could provide!</p>