11) Support dma-buf memory management.
2
3In order to zero-copy import camera images into the 3D or display
4pipelines, we need to export our buffers through dma-buf so that the
5vc4 driver can import them.  This may involve bringing in the VCSM
6driver (which allows long-term management of regions of memory in the
7space that the VPU reserved and Linux otherwise doesn't have access
8to), or building some new protocol that allows VCSM-style management
9of Linux's CMA memory.
10
112) Avoid extra copies for padding of images.
12
13We expose V4L2_PIX_FMT_* formats that have a specified stride/height
14padding in the V4L2 spec, but that padding doesn't match what the
15hardware can do.  If we exposed the native padding requirements
16through the V4L2 "multiplanar" formats, the firmware would have one
17less copy it needed to do.
18