gpu: ion: Use writecombine for uncached mappings

When we map ion buffers as uncached we want to map them as
uncached but still be able to use buffering of transactions
since turning off buffering has a severe performance impact.

Change-Id: I5a09ac34bd3ce3f001d10d9efd71d140f632564d
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
gpu: ion: Request highmem pages for IOMMU heap

When allocating pages for IOMMU heap it is advantageous
to try to allocate pages from highmem in addition to
lowmem since clients using the IOMMU heap can use
either highmem or lowmem.

CRs-fixed: 430457
Change-Id: Ifc794fc344c67dd53d8f7cebf86536ab9d44ed6c
Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
Use pgprot_writecombine in ion_system_heap_map_kernel for optimization.
msm: kgsl: Enable "big page" memory allocations

Allow users to specify "big page" mode when allocating GPU
memory. This will attempt to allocate contigious units of 64k
bytes per instead of the usual PAGE_SIZE units.  If the allocation
fails, then automatically fall back to allocate the rest of the
region with 4K pages. This means that potentially any allocation
could be comprised of a mixture of 64k chunks and 4k chunks.

Change-Id: Ic0dedbadcf1f4b30a106f430dd2d87781ea54829
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>