Add support for non-coherent DMA, either by performing explicit cache maintenance when DMA mappings are aligned to the CPU's DMA buffer alignment, or by bounce buffering via uncached mappings otherwise. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Marcin Wojtas <mw@semihalf.com> Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>