media: videobuf2: fix buffer management issues

Use right buffer flag NVMAP_HANDLE_WRITE_COMBINE to allocate buffer,
which can be shared by VI/CSI and CPU. Don't use NVMAP_HEAP_SYSMEM.
It is validated to old T20 silicon and can't support big buffers. By
default, our nvmap_alloc() will use IOVMM to allocate buffers.

nvmap_pin() gives us IOVA for hardware engines like VI/CSI module
with IOMMU enabled in kernel. nvmap_mmap() gives us VA for CPU
read/write operations. So we need to convert VA address to physical
address of the buffer and map that buffer to user space processor's
memory space "page by page".

Bug 1369083

Change-Id: I4629eebe206c7640adf63551968fd89260dd0082
Signed-off-by: Bryan Wu <pengw@nvidia.com>
Reviewed-on: http://git-master/r/279984
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Allen Martin <amartin@nvidia.com>
Reviewed-by: Matthew Pedro <mapedro@nvidia.com>
Tested-by: Matthew Pedro <mapedro@nvidia.com>

0 files changed, 0 insertions, 0 deletions