Because there might be more than a single call to CreateSurfaces,
we cannot assume that the index relative to the number of surfaces
requested in a single call matches the v4l2 index.
Grab the base index (as returned by the kernel) when allocating
buffers and use it for memory mapping and addressing them in v4l2.
This avoids memory-mapping the first (index 0) buffer multiple times
in that scenario instead of the n-th allocated buffer (in the n-th
call in the sequence).
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Although this is not needed when using the combination of CREATE_BUFS and
QUERYBUF V4L2 ioctls (as currently done) to allocate and prepare buffers,
the REQBUF ioctl is useful to liberate the buffers after use.
This introduces a helper for this purpose.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Since the V4L2 ioctl is called QUERYBUF, it makes more sense to
call the associated function with the same name.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
The coding style has been a bit erratic. Enforce the linux kernel coding
style by reusing their .clang-format file, running clang-format on the
source, and ignoring the few shortcomings that clang-format has at the
moment (especially on aligning the define values).
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Paul Kocialkowski