[Linaro-mm-sig] Buffer sharing proof-of-concept

Hello Everyone,

This patchset introduces the proof-of-concept infrastructure for buffer sharing between multiple devices using file descriptors. The infrastructure has been integrated with V4L2 framework, more specifically videobuf2 and two S5P drivers FIMC (capture interface) and TV drivers, but it can be easily used by other kernel subsystems, like DRI.

In this patch the buffer object has been simplified to absolute minimum - it contains only the buffer physical address (only physically contiguous buffers are supported), but this can be easily extended to complete scatter list in the future.

Best regards